SCons: Review uses of CCFLAGS, CXXFLAGS and CPPFLAGS

Many contributors (me included) did not fully understand what CCFLAGS,
CXXFLAGS and CPPFLAGS refer to exactly, and were thus not using them
in the way they are intended to be.

As per the SCons manual: https://www.scons.org/doc/HTML/scons-user/apa.html

- CCFLAGS: General options that are passed to the C and C++ compilers.
- CFLAGS: General options that are passed to the C compiler (C only;
  not C++).
- CXXFLAGS: General options that are passed to the C++ compiler. By
  default, this includes the value of $CCFLAGS, so that setting
  $CCFLAGS affects both C and C++ compilation.
- CPPFLAGS: User-specified C preprocessor options. These will be
  included in any command that uses the C preprocessor, including not
  just compilation of C and C++ source files [...], but also [...]
  Fortran [...] and [...] assembly language source file[s].

TL;DR: Compiler options go to CCFLAGS, unless they must be restricted
to either C (CFLAGS) or C++ (CXXFLAGS). Preprocessor defines go to
CPPFLAGS.

23 files changed, 122 insertions, 101 deletions

diff --git a/SConstruct b/SConstruct
index 6bb129a174..e943f8dc04 100644
--- a/SConstruct
+++ b/SConstruct
@@ -161,8 +161,8 @@ opts.Add("CXX", "C++ compiler")
 opts.Add("CC", "C compiler")
 opts.Add("LINK", "Linker")
 opts.Add("CCFLAGS", "Custom flags for both the C and C++ compilers")
-opts.Add("CXXFLAGS", "Custom flags for the C++ compiler")
 opts.Add("CFLAGS", "Custom flags for the C compiler")
+opts.Add("CXXFLAGS", "Custom flags for the C++ compiler")
 opts.Add("LINKFLAGS", "Custom flags for the linker")
 
 # add platform specific options
@@ -271,17 +271,18 @@ if selected_platform in platform_list:
 
     CCFLAGS = env.get('CCFLAGS', '')
     env['CCFLAGS'] = ''
-
     env.Append(CCFLAGS=str(CCFLAGS).split())
 
     CFLAGS = env.get('CFLAGS', '')
     env['CFLAGS'] = ''
-
     env.Append(CFLAGS=str(CFLAGS).split())
 
+    CXXFLAGS = env.get('CXXFLAGS', '')
+    env['CXXFLAGS'] = ''
+    env.Append(CXXFLAGS=str(CXXFLAGS).split())
+
     LINKFLAGS = env.get('LINKFLAGS', '')
     env['LINKFLAGS'] = ''
-
     env.Append(LINKFLAGS=str(LINKFLAGS).split())
 
     flag_list = platform_flags[selected_platform]
@@ -322,15 +323,16 @@ if selected_platform in platform_list:
             # FIXME: enable -Wlogical-op and -Wduplicated-branches once #27594 is merged
             # Note: enable -Wimplicit-fallthrough for Clang (already part of -Wextra for GCC)
             # once we switch to C++11 or later (necessary for our FALLTHROUGH macro).
-            env.Append(CCFLAGS=['-Wall', '-Wextra', '-Wno-unused-parameter',
-                '-Wctor-dtor-privacy', '-Wnon-virtual-dtor']
+            env.Append(CCFLAGS=['-Wall', '-Wextra', '-Wno-unused-parameter']
                 + all_plus_warnings + shadow_local_warning)
+            env.Append(CXXFLAGS=['-Wctor-dtor-privacy', '-Wnon-virtual-dtor'])
             if methods.using_gcc(env):
-                env['CCFLAGS'] += ['-Wno-clobbered', '-Walloc-zero', '-Wnoexcept',
-                    '-Wduplicated-cond', '-Wplacement-new=1', '-Wstringop-overflow=4']
+                env.Append(CCFLAGS=['-Wno-clobbered', '-Walloc-zero',
+                    '-Wduplicated-cond', '-Wstringop-overflow=4'])
+                env.Append(CXXFLAGS=['-Wnoexcept', '-Wplacement-new=1'])
                 version = methods.get_compiler_version(env)
                 if version != None and version[0] >= '9':
-                    env['CCFLAGS'] += ['-Wattribute-alias=2']
+                    env.Append(CCFLAGS=['-Wattribute-alias=2'])
         elif (env["warnings"] == 'all'):
             env.Append(CCFLAGS=['-Wall'] + shadow_local_warning)
         elif (env["warnings"] == 'moderate'):
diff --git a/core/SCsub b/core/SCsub
index 00d0bcac24..d5be74a64f 100644
--- a/core/SCsub
+++ b/core/SCsub
@@ -129,10 +129,10 @@ if env['builtin_zstd']:
     thirdparty_zstd_sources = [thirdparty_zstd_dir + file for file in thirdparty_zstd_sources]
 
     env_thirdparty.Append(CPPPATH=[thirdparty_zstd_dir, thirdparty_zstd_dir + "common"])
-    env_thirdparty.Append(CCFLAGS="-DZSTD_STATIC_LINKING_ONLY")
+    env_thirdparty.Append(CPPFLAGS="-DZSTD_STATIC_LINKING_ONLY")
     env.Append(CPPPATH=thirdparty_zstd_dir)
     # Also needed in main env includes will trigger warnings
-    env.Append(CCFLAGS="-DZSTD_STATIC_LINKING_ONLY")
+    env.Append(CPPFLAGS="-DZSTD_STATIC_LINKING_ONLY")
 
     env_thirdparty.add_source_files(env.core_sources, thirdparty_zstd_sources)
 
diff --git a/drivers/xaudio2/SCsub b/drivers/xaudio2/SCsub
index 3dca95b429..dfc877b6f5 100644
--- a/drivers/xaudio2/SCsub
+++ b/drivers/xaudio2/SCsub
@@ -3,5 +3,5 @@
 Import('env')
 
 env.add_source_files(env.drivers_sources, "*.cpp")
-env.Append(CXXFLAGS=['-DXAUDIO2_ENABLED'])
+env.Append(CPPFLAGS=['-DXAUDIO2_ENABLED'])
 env.Append(LINKFLAGS=['xaudio2_8.lib'])
diff --git a/methods.py b/methods.py
index 9efd8bf2f4..11efd68ce4 100644
--- a/methods.py
+++ b/methods.py
@@ -29,11 +29,11 @@ def disable_warnings(self):
         self.Append(CPPFLAGS=['/w'])
         self['CCFLAGS'] = [x for x in self['CCFLAGS'] if not x in warn_flags]
         self['CFLAGS'] = [x for x in self['CFLAGS'] if not x in warn_flags]
-        self['CPPFLAGS'] = [x for x in self['CPPFLAGS'] if not x in warn_flags]
+        self['CXXFLAGS'] = [x for x in self['CXXFLAGS'] if not x in warn_flags]
     else:
         self.Append(CCFLAGS=['-w'])
         self.Append(CFLAGS=['-w'])
-        self.Append(CPPFLAGS=['-w'])
+        self.Append(CXXFLAGS=['-w'])
 
 
 def add_module_version_string(self,s):
diff --git a/modules/bullet/SCsub b/modules/bullet/SCsub
index 7e714ba43f..e7c2fff54c 100644
--- a/modules/bullet/SCsub
+++ b/modules/bullet/SCsub
@@ -188,7 +188,7 @@ if env['builtin_bullet']:
 
     env_bullet.Append(CPPPATH=[thirdparty_dir])
     # if env['target'] == "debug" or env['target'] == "release_debug":
-    #     env_bullet.Append(CCFLAGS=['-DBT_DEBUG'])
+    #     env_bullet.Append(CPPFLAGS=['-DBT_DEBUG'])
 
     env_thirdparty = env_bullet.Clone()
     env_thirdparty.disable_warnings()
diff --git a/modules/etc/SCsub b/modules/etc/SCsub
index 6e963ef766..eb2738053b 100644
--- a/modules/etc/SCsub
+++ b/modules/etc/SCsub
@@ -31,7 +31,7 @@ env_etc.Append(CPPPATH=[thirdparty_dir])
 
 # upstream uses c++11
 if not env.msvc:
-	env_etc.Append(CCFLAGS="-std=c++11")
+	env_etc.Append(CXXFLAGS="-std=c++11")
 
 env_thirdparty = env_etc.Clone()
 env_thirdparty.disable_warnings()
diff --git a/modules/freetype/SCsub b/modules/freetype/SCsub
index c2d165f367..f2cd9f9a60 100644
--- a/modules/freetype/SCsub
+++ b/modules/freetype/SCsub
@@ -72,9 +72,9 @@ if env['builtin_freetype']:
     # Also needed in main env for scene/
     env.Append(CPPPATH=[thirdparty_dir + "/include"])
 
-    env_freetype.Append(CCFLAGS=['-DFT2_BUILD_LIBRARY', '-DFT_CONFIG_OPTION_USE_PNG'])
+    env_freetype.Append(CPPFLAGS=['-DFT2_BUILD_LIBRARY', '-DFT_CONFIG_OPTION_USE_PNG'])
     if (env['target'] != 'release'):
-        env_freetype.Append(CCFLAGS=['-DZLIB_DEBUG'])
+        env_freetype.Append(CPPFLAGS=['-DZLIB_DEBUG'])
 
     # Also requires libpng headers
     if env['builtin_libpng']:
@@ -100,4 +100,4 @@ if env['builtin_freetype']:
 # Godot source files
 env_freetype.add_source_files(env.modules_sources, "*.cpp")
 # Used in scene/, needs to be in main env
-env.Append(CCFLAGS=['-DFREETYPE_ENABLED'])
+env.Append(CPPFLAGS=['-DFREETYPE_ENABLED'])
diff --git a/modules/opus/SCsub b/modules/opus/SCsub
index b72144c679..a1325734e2 100644
--- a/modules/opus/SCsub
+++ b/modules/opus/SCsub
@@ -139,7 +139,7 @@ if env['builtin_opus']:
     opus_sources_silk = []
 
     if env["platform"] in ["android", "iphone", "javascript"]:
-        env_opus.Append(CFLAGS=["-DFIXED_POINT"])
+        env_opus.Append(CPPFLAGS=["-DFIXED_POINT"])
         opus_sources_silk = [
             "silk/fixed/LTP_analysis_filter_FIX.c",
             "silk/fixed/LTP_scale_ctrl_FIX.c",
@@ -208,7 +208,7 @@ if env['builtin_opus']:
     if env['builtin_libogg']:
         env_opus.Append(CPPPATH=["#thirdparty/libogg"])
 
-    env_opus.Append(CFLAGS=["-DHAVE_CONFIG_H"])
+    env_opus.Append(CPPFLAGS=["-DHAVE_CONFIG_H"])
 
     thirdparty_include_paths = [
         "",
@@ -222,14 +222,14 @@ if env['builtin_opus']:
 
     if env["platform"] == "android":
         if ("android_arch" in env and env["android_arch"] in ["armv6", "armv7"]):
-            env_opus.Append(CFLAGS=["-DOPUS_ARM_OPT"])
+            env_opus.Append(CPPFLAGS=["-DOPUS_ARM_OPT"])
         elif ("android_arch" in env and env["android_arch"] == "arm64v8"):
-            env_opus.Append(CFLAGS=["-DOPUS_ARM64_OPT"])
+            env_opus.Append(CPPFLAGS=["-DOPUS_ARM64_OPT"])
     elif env["platform"] == "iphone":
         if ("arch" in env and env["arch"] == "arm"):
-            env_opus.Append(CFLAGS=["-DOPUS_ARM_OPT"])
+            env_opus.Append(CPPFLAGS=["-DOPUS_ARM_OPT"])
         elif ("arch" in env and env["arch"] == "arm64"):
-            env_opus.Append(CFLAGS=["-DOPUS_ARM64_OPT"])
+            env_opus.Append(CPPFLAGS=["-DOPUS_ARM64_OPT"])
 
     env_thirdparty = env_opus.Clone()
     env_thirdparty.disable_warnings()
diff --git a/modules/svg/SCsub b/modules/svg/SCsub
index 22f0b1e3eb..66d9b3bf75 100644
--- a/modules/svg/SCsub
+++ b/modules/svg/SCsub
@@ -16,7 +16,7 @@ env_svg.Append(CPPPATH=[thirdparty_dir])
 # FIXME: Needed in editor/editor_themes.cpp for now, but ideally there
 # shouldn't be a dependency on modules/ and its own 3rd party deps.
 env.Append(CPPPATH=[thirdparty_dir])
-env.Append(CCFLAGS=["-DSVG_ENABLED"])
+env.Append(CPPFLAGS=["-DSVG_ENABLED"])
 
 env_thirdparty = env_svg.Clone()
 env_thirdparty.disable_warnings()
diff --git a/modules/theora/SCsub b/modules/theora/SCsub
index 98c4274a7e..f98db2359c 100644
--- a/modules/theora/SCsub
+++ b/modules/theora/SCsub
@@ -66,7 +66,7 @@ if env['builtin_libtheora']:
         thirdparty_sources += thirdparty_sources_x86_vc
 
     if (env["x86_libtheora_opt_gcc"] or env["x86_libtheora_opt_vc"]):
-        env_theora.Append(CCFLAGS=["-DOC_X86_ASM"])
+        env_theora.Append(CPPFLAGS=["-DOC_X86_ASM"])
 
     thirdparty_sources = [thirdparty_dir + file for file in thirdparty_sources]
 
diff --git a/modules/vhacd/SCsub b/modules/vhacd/SCsub
index 11cd5f4743..fdd3ddc1e6 100644
--- a/modules/vhacd/SCsub
+++ b/modules/vhacd/SCsub
@@ -29,7 +29,7 @@ env_vhacd.Append(CPPFLAGS=["-DGODOT_ENET"])
 
 # upstream uses c++11
 if not env.msvc:
-	env_vhacd.Append(CCFLAGS="-std=c++11")
+	env_vhacd.Append(CXXFLAGS="-std=c++11")
 
 env_thirdparty = env_vhacd.Clone()
 env_thirdparty.disable_warnings()
diff --git a/modules/webm/SCsub b/modules/webm/SCsub
index cb35b926ab..dcc9a45044 100644
--- a/modules/webm/SCsub
+++ b/modules/webm/SCsub
@@ -19,7 +19,7 @@ env_webm.Append(CPPPATH=[thirdparty_dir, thirdparty_dir + "libwebm/"])
 
 # upstream uses c++11
 if (not env_webm.msvc):
-	env_webm.Append(CCFLAGS="-std=c++11")
+	env_webm.Append(CXXFLAGS="-std=c++11")
 
 # also requires libogg, libvorbis and libopus
 if env['builtin_libogg']:
diff --git a/modules/webm/libvpx/SCsub b/modules/webm/libvpx/SCsub
index 2639d20620..5bf4ea3464 100644
--- a/modules/webm/libvpx/SCsub
+++ b/modules/webm/libvpx/SCsub
@@ -323,7 +323,7 @@ if webm_cpu_x86:
     elif cpu_bits == '64':
         env_libvpx["ASCPU"] = 'X86_64'
 
-    env_libvpx.Append(CCFLAGS=['-DWEBM_X86ASM'])
+    env_libvpx.Append(CPPFLAGS=['-DWEBM_X86ASM'])
 
     webm_simd_optimizations = True
 
@@ -337,7 +337,7 @@ if webm_cpu_arm:
         env_libvpx["ASFLAGS"] = ''
         env_libvpx["ASCOM"] = '$AS $ASFLAGS -o $TARGET $SOURCES'
 
-    env_libvpx.Append(CCFLAGS=['-DWEBM_ARMASM'])
+    env_libvpx.Append(CPPFLAGS=['-DWEBM_ARMASM'])
 
     webm_simd_optimizations = True
 
diff --git a/modules/websocket/SCsub b/modules/websocket/SCsub
index 0345e533bc..12b4969cf7 100644
--- a/modules/websocket/SCsub
+++ b/modules/websocket/SCsub
@@ -88,7 +88,7 @@ if env['builtin_libwebsockets'] and not env["platform"] == "javascript": # alrea
         env_lws.Append(CPPPATH=[helper_dir])
 
     if env["platform"] == "uwp":
-        env_lws.Append(CCFLAGS=["/DLWS_MINGW_SUPPORT"])
+        env_lws.Append(CPPFLAGS=["/DLWS_MINGW_SUPPORT"])
 
     env_thirdparty = env_lws.Clone()
     env_thirdparty.disable_warnings()
diff --git a/modules/xatlas_unwrap/SCsub b/modules/xatlas_unwrap/SCsub
index ad364d5aaf..b8adfcb7df 100644
--- a/modules/xatlas_unwrap/SCsub
+++ b/modules/xatlas_unwrap/SCsub
@@ -24,18 +24,18 @@ if env['builtin_xatlas']:
     if env["platform"] == 'x11':
         # if not specifically one of the *BSD, then use LINUX as default
         if platform.system() == "FreeBSD":
-            env_xatlas_unwrap.Append(CCFLAGS=["-DNV_OS_FREEBSD", "-DPOSH_COMPILER_GCC"])
+            env_xatlas_unwrap.Append(CPPFLAGS=["-DNV_OS_FREEBSD", "-DPOSH_COMPILER_GCC"])
         elif platform.system() == "OpenBSD":
-            env_xatlas_unwrap.Append(CCFLAGS=["-DNV_OS_OPENBSD", "-DPOSH_COMPILER_GCC"])
+            env_xatlas_unwrap.Append(CPPFLAGS=["-DNV_OS_OPENBSD", "-DPOSH_COMPILER_GCC"])
         else:
-            env_xatlas_unwrap.Append(CCFLAGS=["-DNV_OS_LINUX", "-DPOSH_COMPILER_GCC"])
+            env_xatlas_unwrap.Append(CPPFLAGS=["-DNV_OS_LINUX", "-DPOSH_COMPILER_GCC"])
     elif env["platform"] == 'osx':
-        env_xatlas_unwrap.Append(CCFLAGS=["-DNV_OS_DARWIN", "-DPOSH_COMPILER_GCC"])
+        env_xatlas_unwrap.Append(CPPFLAGS=["-DNV_OS_DARWIN", "-DPOSH_COMPILER_GCC"])
     elif env["platform"] == 'windows':
         if env.msvc:
-            env_xatlas_unwrap.Append(CCFLAGS=["-DNV_OS_WIN32", "-DNV_CC_MSVC", "-DPOSH_COMPILER_MSVC" ])
+            env_xatlas_unwrap.Append(CPPFLAGS=["-DNV_OS_WIN32", "-DNV_CC_MSVC", "-DPOSH_COMPILER_MSVC" ])
         else:
-            env_xatlas_unwrap.Append(CCFLAGS=["-DNV_OS_MINGW", "-DNV_CC_GNUC", "-DPOSH_COMPILER_GCC", "-U__STRICT_ANSI__"])
+            env_xatlas_unwrap.Append(CPPFLAGS=["-DNV_OS_MINGW", "-DNV_CC_GNUC", "-DPOSH_COMPILER_GCC", "-U__STRICT_ANSI__"])
             env.Append(LIBS=["dbghelp"])
 
     env_thirdparty = env_xatlas_unwrap.Clone()
diff --git a/platform/android/detect.py b/platform/android/detect.py
index 5623274050..6c67067db7 100644
--- a/platform/android/detect.py
+++ b/platform/android/detect.py
@@ -150,19 +150,21 @@ def configure(env):
     if (env["target"].startswith("release")):
         if (env["optimize"] == "speed"): #optimize for speed (default)
             env.Append(LINKFLAGS=['-O2'])
-            env.Append(CPPFLAGS=['-O2', '-DNDEBUG', '-fomit-frame-pointer'])
+            env.Append(CCFLAGS=['-O2', '-fomit-frame-pointer'])
+            env.Append(CPPFLAGS=['-DNDEBUG'])
         else: #optimize for size
-            env.Append(CPPFLAGS=['-Os', '-DNDEBUG'])
+            env.Append(CCFLAGS=['-Os'])
+            env.Append(CPPFLAGS=['-DNDEBUG'])
             env.Append(LINKFLAGS=['-Os'])
 
         if (can_vectorize):
-            env.Append(CPPFLAGS=['-ftree-vectorize'])
+            env.Append(CCFLAGS=['-ftree-vectorize'])
         if (env["target"] == "release_debug"):
             env.Append(CPPFLAGS=['-DDEBUG_ENABLED'])
     elif (env["target"] == "debug"):
         env.Append(LINKFLAGS=['-O0'])
-        env.Append(CPPFLAGS=['-O0', '-D_DEBUG', '-UNDEBUG', '-DDEBUG_ENABLED',
-                             '-DDEBUG_MEMORY_ENABLED', '-g', '-fno-limit-debug-info'])
+        env.Append(CCFLAGS=['-O0', '-g', '-fno-limit-debug-info'])
+        env.Append(CPPFLAGS=['-D_DEBUG', '-UNDEBUG', '-DDEBUG_ENABLED', '-DDEBUG_MEMORY_ENABLED'])
 
     ## Compiler configuration
 
@@ -216,15 +218,16 @@ def configure(env):
     if env['android_stl']:
         env.Append(CPPFLAGS=["-isystem", env["ANDROID_NDK_ROOT"] + "/sources/cxx-stl/llvm-libc++/include"])
         env.Append(CPPFLAGS=["-isystem", env["ANDROID_NDK_ROOT"] + "/sources/cxx-stl/llvm-libc++abi/include"])
-        env.Append(CXXFLAGS=['-frtti',"-std=gnu++14"])
+        env.Append(CXXFLAGS=['-frtti', "-std=gnu++14"])
     else:
-        env.Append(CXXFLAGS=['-fno-rtti', '-fno-exceptions', '-DNO_SAFE_CAST'])
+        env.Append(CXXFLAGS=['-fno-rtti', '-fno-exceptions'])
+        env.Append(CPPFLAGS=['-DNO_SAFE_CAST'])
 
     ndk_version = get_ndk_version(env["ANDROID_NDK_ROOT"])
     if ndk_version != None and LooseVersion(ndk_version) >= LooseVersion("15.0.4075724"):
         print("Using NDK unified headers")
         sysroot = env["ANDROID_NDK_ROOT"] + "/sysroot"
-        env.Append(CPPFLAGS=["--sysroot="+sysroot])
+        env.Append(CPPFLAGS=["--sysroot=" + sysroot])
         env.Append(CPPFLAGS=["-isystem", sysroot + "/usr/include/" + abi_subpath])
         env.Append(CPPFLAGS=["-isystem", env["ANDROID_NDK_ROOT"] + "/sources/android/support/include"])
         # For unified headers this define has to be set manually
@@ -233,48 +236,51 @@ def configure(env):
         print("Using NDK deprecated headers")
         env.Append(CPPFLAGS=["-isystem", lib_sysroot + "/usr/include"])
 
-    env.Append(CPPFLAGS='-fpic -ffunction-sections -funwind-tables -fstack-protector-strong -fvisibility=hidden -fno-strict-aliasing'.split())
+    env.Append(CCFLAGS='-fpic -ffunction-sections -funwind-tables -fstack-protector-strong -fvisibility=hidden -fno-strict-aliasing'.split())
     env.Append(CPPFLAGS='-DNO_STATVFS -DGLES_ENABLED'.split())
 
     env['neon_enabled'] = False
     if env['android_arch'] == 'x86':
         target_opts = ['-target', 'i686-none-linux-android']
         # The NDK adds this if targeting API < 21, so we can drop it when Godot targets it at least
-        env.Append(CPPFLAGS=['-mstackrealign'])
+        env.Append(CCFLAGS=['-mstackrealign'])
 
     elif env['android_arch'] == 'x86_64':
         target_opts = ['-target', 'x86_64-none-linux-android']
 
     elif env["android_arch"] == "armv6":
         target_opts = ['-target', 'armv6-none-linux-androideabi']
-        env.Append(CPPFLAGS='-D__ARM_ARCH_6__ -march=armv6 -mfpu=vfp -mfloat-abi=softfp'.split())
+        env.Append(CCFLAGS='-march=armv6 -mfpu=vfp -mfloat-abi=softfp'.split())
+        env.Append(CPPFLAGS=['-D__ARM_ARCH_6__'])
 
     elif env["android_arch"] == "armv7":
         target_opts = ['-target', 'armv7-none-linux-androideabi']
-        env.Append(CPPFLAGS='-D__ARM_ARCH_7__ -D__ARM_ARCH_7A__ -march=armv7-a -mfloat-abi=softfp'.split())
+        env.Append(CCFLAGS='-march=armv7-a -mfloat-abi=softfp'.split())
+        env.Append(CPPFLAGS='-D__ARM_ARCH_7__ -D__ARM_ARCH_7A__'.split())
         if env['android_neon']:
             env['neon_enabled'] = True
-            env.Append(CPPFLAGS=['-mfpu=neon', '-D__ARM_NEON__'])
+            env.Append(CCFLAGS=['-mfpu=neon'])
+            env.Append(CPPFLAGS=['-D__ARM_NEON__'])
         else:
-            env.Append(CPPFLAGS=['-mfpu=vfpv3-d16'])
+            env.Append(CCFLAGS=['-mfpu=vfpv3-d16'])
 
     elif env["android_arch"] == "arm64v8":
         target_opts = ['-target', 'aarch64-none-linux-android']
+        env.Append(CCFLAGS=['-mfix-cortex-a53-835769'])
         env.Append(CPPFLAGS=['-D__ARM_ARCH_8A__'])
-        env.Append(CPPFLAGS=['-mfix-cortex-a53-835769'])
 
-    env.Append(CPPFLAGS=target_opts)
-    env.Append(CPPFLAGS=common_opts)
+    env.Append(CCFLAGS=target_opts)
+    env.Append(CCFLAGS=common_opts)
 
     ## Link flags
     if ndk_version != None and LooseVersion(ndk_version) >= LooseVersion("15.0.4075724"):
         if LooseVersion(ndk_version) >= LooseVersion("17.1.4828580"):
-            env.Append(LINKFLAGS=['-Wl,--exclude-libs,libgcc.a','-Wl,--exclude-libs,libatomic.a','-nostdlib++'])
+            env.Append(LINKFLAGS=['-Wl,--exclude-libs,libgcc.a', '-Wl,--exclude-libs,libatomic.a', '-nostdlib++'])
         else:
-            env.Append(LINKFLAGS=[env["ANDROID_NDK_ROOT"] +"/sources/cxx-stl/llvm-libc++/libs/"+arch_subpath+"/libandroid_support.a"])
+            env.Append(LINKFLAGS=[env["ANDROID_NDK_ROOT"] + "/sources/cxx-stl/llvm-libc++/libs/" + arch_subpath + "/libandroid_support.a"])
         env.Append(LINKFLAGS=['-shared', '--sysroot=' + lib_sysroot, '-Wl,--warn-shared-textrel'])
-        env.Append(LIBPATH=[env["ANDROID_NDK_ROOT"] + "/sources/cxx-stl/llvm-libc++/libs/"+arch_subpath+"/"])
-        env.Append(LINKFLAGS=[env["ANDROID_NDK_ROOT"] +"/sources/cxx-stl/llvm-libc++/libs/"+arch_subpath+"/libc++_shared.so"])
+        env.Append(LIBPATH=[env["ANDROID_NDK_ROOT"] + "/sources/cxx-stl/llvm-libc++/libs/" + arch_subpath + "/"])
+        env.Append(LINKFLAGS=[env["ANDROID_NDK_ROOT"] +"/sources/cxx-stl/llvm-libc++/libs/" + arch_subpath + "/libc++_shared.so"])
     else:
         env.Append(LINKFLAGS=['-shared', '--sysroot=' + lib_sysroot, '-Wl,--warn-shared-textrel'])
         if mt_link:
diff --git a/platform/haiku/detect.py b/platform/haiku/detect.py
index ae8cc58a4a..874b1ab1fb 100644
--- a/platform/haiku/detect.py
+++ b/platform/haiku/detect.py
@@ -150,6 +150,6 @@ def configure(env):
     env.Append(CPPPATH=['#platform/haiku'])
     env.Append(CPPFLAGS=['-DUNIX_ENABLED', '-DOPENGL_ENABLED', '-DGLES_ENABLED'])
     env.Append(CPPFLAGS=['-DMEDIA_KIT_ENABLED'])
-    # env.Append(CCFLAGS=['-DFREETYPE_ENABLED'])
+    # env.Append(CPPFLAGS=['-DFREETYPE_ENABLED'])
     env.Append(CPPFLAGS=['-DPTHREAD_NO_RENAME'])  # TODO: enable when we have pthread_setname_np
     env.Append(LIBS=['be', 'game', 'media', 'network', 'bnetapi', 'z', 'GL'])
diff --git a/platform/iphone/detect.py b/platform/iphone/detect.py
index 853f24379e..d56e28a4af 100644
--- a/platform/iphone/detect.py
+++ b/platform/iphone/detect.py
@@ -45,20 +45,21 @@ def configure(env):
     if (env["target"].startswith("release")):
         env.Append(CPPFLAGS=['-DNDEBUG', '-DNS_BLOCK_ASSERTIONS=1'])
         if (env["optimize"] == "speed"): #optimize for speed (default)
-            env.Append(CPPFLAGS=['-O2', '-ftree-vectorize', '-fomit-frame-pointer'])
+            env.Append(CCFLAGS=['-O2', '-ftree-vectorize', '-fomit-frame-pointer'])
             env.Append(LINKFLAGS=['-O2'])
         else: #optimize for size
-            env.Append(CPPFLAGS=['-Os', '-ftree-vectorize'])
+            env.Append(CCFLAGS=['-Os', '-ftree-vectorize'])
             env.Append(LINKFLAGS=['-Os'])
 
         if env["target"] == "release_debug":
             env.Append(CPPFLAGS=['-DDEBUG_ENABLED'])
 
     elif (env["target"] == "debug"):
-        env.Append(CPPFLAGS=['-D_DEBUG', '-DDEBUG=1', '-gdwarf-2', '-O0', '-DDEBUG_ENABLED', '-DDEBUG_MEMORY_ENABLED'])
+        env.Append(CCFLAGS=['-gdwarf-2', '-O0'])
+        env.Append(CPPFLAGS=['-D_DEBUG', '-DDEBUG=1', '-DDEBUG_ENABLED', '-DDEBUG_MEMORY_ENABLED'])
 
     if (env["use_lto"]):
-        env.Append(CPPFLAGS=['-flto'])
+        env.Append(CCFLAGS=['-flto'])
         env.Append(LINKFLAGS=['-flto'])
 
     ## Architecture
@@ -104,7 +105,7 @@ def configure(env):
         detect_darwin_sdk_path('iphonesimulator', env)
         env['ENV']['MACOSX_DEPLOYMENT_TARGET'] = '10.9'
         arch_flag = "i386" if env["arch"] == "x86" else env["arch"]
-        env.Append(CCFLAGS=('-arch ' + arch_flag + ' -fobjc-abi-version=2 -fobjc-legacy-dispatch -fmessage-length=0 -fpascal-strings -fblocks -fasm-blocks -isysroot $IPHONESDK -mios-simulator-version-min=10.0 -DCUSTOM_MATRIX_TRANSFORM_H=\\\"build/iphone/matrix4_iphone.h\\\" -DCUSTOM_VECTOR3_TRANSFORM_H=\\\"build/iphone/vector3_iphone.h\\\"').split())
+        env.Append(CCFLAGS=('-arch ' + arch_flag + ' -fobjc-abi-version=2 -fobjc-legacy-dispatch -fmessage-length=0 -fpascal-strings -fblocks -fasm-blocks -isysroot $IPHONESDK -mios-simulator-version-min=10.0').split())
     elif (env["arch"] == "arm"):
         detect_darwin_sdk_path('iphone', env)
         env.Append(CCFLAGS='-fno-objc-arc -arch armv7 -fmessage-length=0 -fno-strict-aliasing -fdiagnostics-print-source-range-info -fdiagnostics-show-category=id -fdiagnostics-parseable-fixits -fpascal-strings -fblocks -isysroot $IPHONESDK -fvisibility=hidden -mthumb "-DIBOutlet=__attribute__((iboutlet))" "-DIBOutletCollection(ClassName)=__attribute__((iboutletcollection(ClassName)))" "-DIBAction=void)__attribute__((ibaction)" -miphoneos-version-min=10.0 -MMD -MT dependencies'.split())
@@ -115,9 +116,9 @@ def configure(env):
         env.Append(CPPFLAGS=['-DLIBYUV_DISABLE_NEON'])
 
     if env['ios_exceptions']:
-        env.Append(CPPFLAGS=['-fexceptions'])
+        env.Append(CCFLAGS=['-fexceptions'])
     else:
-        env.Append(CPPFLAGS=['-fno-exceptions'])
+        env.Append(CCFLAGS=['-fno-exceptions'])
 
     ## Link flags
 
diff --git a/platform/osx/detect.py b/platform/osx/detect.py
index 36a753e683..8024897195 100644
--- a/platform/osx/detect.py
+++ b/platform/osx/detect.py
@@ -53,16 +53,18 @@ def configure(env):
 
     elif (env["target"] == "release_debug"):
         if (env["optimize"] == "speed"): #optimize for speed (default)
-            env.Prepend(CCFLAGS=['-O2', '-DDEBUG_ENABLED'])
+            env.Prepend(CCFLAGS=['-O2'])
         else: #optimize for size
-            env.Prepend(CCFLAGS=['-Os', '-DDEBUG_ENABLED'])
+            env.Prepend(CCFLAGS=['-Os'])
+        env.Prepend(CPPFLAGS=['-DDEBUG_ENABLED'])
         if (env["debug_symbols"] == "yes"):
             env.Prepend(CCFLAGS=['-g1'])
         if (env["debug_symbols"] == "full"):
             env.Prepend(CCFLAGS=['-g2'])
 
     elif (env["target"] == "debug"):
-        env.Prepend(CCFLAGS=['-g3', '-DDEBUG_ENABLED', '-DDEBUG_MEMORY_ENABLED'])
+        env.Prepend(CCFLAGS=['-g3'])
+        env.Prepend(CPPFLAGS=['-DDEBUG_ENABLED', '-DDEBUG_MEMORY_ENABLED'])
 
     ## Architecture
 
@@ -88,10 +90,10 @@ def configure(env):
             env['AR'] = mpprefix + "/libexec/llvm-" + mpclangver + "/bin/llvm-ar"
             env['RANLIB'] = mpprefix + "/libexec/llvm-" + mpclangver + "/bin/llvm-ranlib"
             env['AS'] = mpprefix + "/libexec/llvm-" + mpclangver + "/bin/llvm-as"
-            env.Append(CCFLAGS=['-D__MACPORTS__']) #hack to fix libvpx MM256_BROADCASTSI128_SI256 define
+            env.Append(CPPFLAGS=['-D__MACPORTS__']) #hack to fix libvpx MM256_BROADCASTSI128_SI256 define
 
         detect_darwin_sdk_path('osx', env)
-        env.Append(CPPFLAGS=['-isysroot', '$MACOS_SDK_PATH'])
+        env.Append(CCFLAGS=['-isysroot', '$MACOS_SDK_PATH'])
         env.Append(LINKFLAGS=['-isysroot', '$MACOS_SDK_PATH'])
 
     else: # osxcross build
@@ -110,7 +112,7 @@ def configure(env):
         env['AR'] = basecmd + "ar"
         env['RANLIB'] = basecmd + "ranlib"
         env['AS'] = basecmd + "as"
-        env.Append(CCFLAGS=['-D__MACPORTS__']) #hack to fix libvpx MM256_BROADCASTSI128_SI256 define
+        env.Append(CPPFLAGS=['-D__MACPORTS__']) #hack to fix libvpx MM256_BROADCASTSI128_SI256 define
 
     if (env["CXX"] == "clang++"):
         env.Append(CPPFLAGS=['-DTYPED_METHOD_BIND'])
@@ -129,5 +131,5 @@ def configure(env):
     env.Append(LINKFLAGS=['-framework', 'Cocoa', '-framework', 'Carbon', '-framework', 'OpenGL', '-framework', 'AGL', '-framework', 'AudioUnit', '-framework', 'CoreAudio', '-framework', 'CoreMIDI', '-lz', '-framework', 'IOKit', '-framework', 'ForceFeedback', '-framework', 'CoreVideo'])
     env.Append(LIBS=['pthread'])
 
-    env.Append(CPPFLAGS=['-mmacosx-version-min=10.9'])
+    env.Append(CCFLAGS=['-mmacosx-version-min=10.9'])
     env.Append(LINKFLAGS=['-mmacosx-version-min=10.9'])
diff --git a/platform/server/detect.py b/platform/server/detect.py
index f13ee72fd2..5306a2bf69 100644
--- a/platform/server/detect.py
+++ b/platform/server/detect.py
@@ -63,9 +63,10 @@ def configure(env):
 
     elif (env["target"] == "release_debug"):
         if (env["optimize"] == "speed"): #optimize for speed (default)
-            env.Prepend(CCFLAGS=['-O2', '-DDEBUG_ENABLED'])
+            env.Prepend(CCFLAGS=['-O2'])
         else: #optimize for size
-            env.Prepend(CCFLAGS=['-Os', '-DDEBUG_ENABLED'])
+            env.Prepend(CCFLAGS=['-Os'])
+        env.Prepend(CPPFLAGS=['-DDEBUG_ENABLED'])
 
         if (env["debug_symbols"] == "yes"):
             env.Prepend(CCFLAGS=['-g1'])
@@ -73,7 +74,8 @@ def configure(env):
             env.Prepend(CCFLAGS=['-g2'])
 
     elif (env["target"] == "debug"):
-        env.Prepend(CCFLAGS=['-g3', '-DDEBUG_ENABLED', '-DDEBUG_MEMORY_ENABLED'])
+        env.Prepend(CCFLAGS=['-g3'])
+        env.Prepend(CPPFLAGS=['-DDEBUG_ENABLED', '-DDEBUG_MEMORY_ENABLED'])
         env.Append(LINKFLAGS=['-rdynamic'])
 
     ## Architecture
diff --git a/platform/uwp/detect.py b/platform/uwp/detect.py
index f8f1b066f6..17f8242466 100644
--- a/platform/uwp/detect.py
+++ b/platform/uwp/detect.py
@@ -53,18 +53,20 @@ def configure(env):
     ## Build type
 
     if (env["target"] == "release"):
-        env.Append(CPPFLAGS=['/O2', '/GL'])
-        env.Append(CPPFLAGS=['/MD'])
+        env.Append(CCFLAGS=['/O2', '/GL'])
+        env.Append(CCFLAGS=['/MD'])
         env.Append(LINKFLAGS=['/SUBSYSTEM:WINDOWS', '/LTCG'])
 
     elif (env["target"] == "release_debug"):
-        env.Append(CCFLAGS=['/O2', '/Zi', '/DDEBUG_ENABLED'])
-        env.Append(CPPFLAGS=['/MD'])
+        env.Append(CCFLAGS=['/O2', '/Zi'])
+        env.Append(CCFLAGS=['/MD'])
+        env.Append(CPPFLAGS=['/DDEBUG_ENABLED'])
         env.Append(LINKFLAGS=['/SUBSYSTEM:CONSOLE'])
 
     elif (env["target"] == "debug"):
-        env.Append(CCFLAGS=['/Zi', '/DDEBUG_ENABLED', '/DDEBUG_MEMORY_ENABLED'])
-        env.Append(CPPFLAGS=['/MDd'])
+        env.Append(CCFLAGS=['/Zi'])
+        env.Append(CCFLAGS=['/MDd'])
+        env.Append(CPPFLAGS=['/DDEBUG_ENABLED', '/DDEBUG_MEMORY_ENABLED'])
         env.Append(LINKFLAGS=['/SUBSYSTEM:CONSOLE'])
         env.Append(LINKFLAGS=['/DEBUG'])
 
@@ -136,18 +138,19 @@ def configure(env):
     ## Compile flags
 
     env.Append(CPPPATH=['#platform/uwp', '#drivers/windows'])
-    env.Append(CCFLAGS=['/DUWP_ENABLED', '/DWINDOWS_ENABLED', '/DTYPED_METHOD_BIND'])
-    env.Append(CCFLAGS=['/DGLES_ENABLED', '/DGL_GLEXT_PROTOTYPES', '/DEGL_EGLEXT_PROTOTYPES', '/DANGLE_ENABLED'])
+    env.Append(CPPFLAGS=['/DUWP_ENABLED', '/DWINDOWS_ENABLED', '/DTYPED_METHOD_BIND'])
+    env.Append(CPPFLAGS=['/DGLES_ENABLED', '/DGL_GLEXT_PROTOTYPES', '/DEGL_EGLEXT_PROTOTYPES', '/DANGLE_ENABLED'])
     winver = "0x0602" # Windows 8 is the minimum target for UWP build
-    env.Append(CCFLAGS=['/DWINVER=%s' % winver, '/D_WIN32_WINNT=%s' % winver])
+    env.Append(CPPFLAGS=['/DWINVER=%s' % winver, '/D_WIN32_WINNT=%s' % winver])
 
-    env.Append(CPPFLAGS=['/D', '__WRL_NO_DEFAULT_LIB__', '/D', 'WIN32', '/DPNG_ABORT=abort'])
+    env.Append(CPPFLAGS=['/D__WRL_NO_DEFAULT_LIB__', '/DWIN32', '/DPNG_ABORT=abort'])
 
     env.Append(CPPFLAGS=['/AI', vc_base_path + 'lib/store/references'])
     env.Append(CPPFLAGS=['/AI', vc_base_path + 'lib/x86/store/references'])
 
-    env.Append(CCFLAGS='/FS /MP /GS /wd"4453" /wd"28204" /wd"4291" /Zc:wchar_t /Gm- /fp:precise /D "_UNICODE" /D "UNICODE" /D "WINAPI_FAMILY=WINAPI_FAMILY_APP" /errorReport:prompt /WX- /Zc:forScope /Gd /EHsc /nologo'.split())
-    env.Append(CXXFLAGS='/ZW /FS'.split())
+    env.Append(CCFLAGS='/FS /MP /GS /wd"4453" /wd"28204" /wd"4291" /Zc:wchar_t /Gm- /fp:precise /errorReport:prompt /WX- /Zc:forScope /Gd /EHsc /nologo'.split())
+    env.Append(CPPFLAGS=['/D_UNICODE', '/DUNICODE', '/D "WINAPI_FAMILY=WINAPI_FAMILY_APP"'])
+    env.Append(CXXFLAGS=['/ZW'])
     env.Append(CCFLAGS=['/AI', vc_base_path + '\\vcpackages', '/AI', os.environ['WINDOWSSDKDIR'] + '\\References\\CommonConfiguration\\Neutral'])
 
     ## Link flags
diff --git a/platform/windows/detect.py b/platform/windows/detect.py
index e986c47b40..5c38eebf04 100644
--- a/platform/windows/detect.py
+++ b/platform/windows/detect.py
@@ -273,7 +273,8 @@ def configure_mingw(env):
            env.Prepend(CCFLAGS=['-g2'])
 
     elif (env["target"] == "release_debug"):
-        env.Append(CCFLAGS=['-O2', '-DDEBUG_ENABLED'])
+        env.Append(CCFLAGS=['-O2'])
+        env.Append(CPPFLAGS=['-DDEBUG_ENABLED'])
         if (env["debug_symbols"] == "yes"):
            env.Prepend(CCFLAGS=['-g1'])
         if (env["debug_symbols"] == "full"):
@@ -284,7 +285,8 @@ def configure_mingw(env):
            env.Prepend(CCFLAGS=['-Os'])
 
     elif (env["target"] == "debug"):
-        env.Append(CCFLAGS=['-g3', '-DDEBUG_ENABLED', '-DDEBUG_MEMORY_ENABLED'])
+        env.Append(CCFLAGS=['-g3'])
+        env.Append(CPPFLAGS=['-DDEBUG_ENABLED', '-DDEBUG_MEMORY_ENABLED'])
 
     ## Compiler configuration
 
@@ -325,11 +327,12 @@ def configure_mingw(env):
 
     ## Compile flags
 
-    env.Append(CCFLAGS=['-DWINDOWS_ENABLED', '-mwindows'])
-    env.Append(CCFLAGS=['-DOPENGL_ENABLED'])
-    env.Append(CCFLAGS=['-DWASAPI_ENABLED'])
-    env.Append(CCFLAGS=['-DWINMIDI_ENABLED'])
-    env.Append(CCFLAGS=['-DWINVER=%s' % env['target_win_version'], '-D_WIN32_WINNT=%s' % env['target_win_version']])
+    env.Append(CCFLAGS=['-mwindows'])
+    env.Append(CPPFLAGS=['-DWINDOWS_ENABLED'])
+    env.Append(CPPFLAGS=['-DOPENGL_ENABLED'])
+    env.Append(CPPFLAGS=['-DWASAPI_ENABLED'])
+    env.Append(CPPFLAGS=['-DWINMIDI_ENABLED'])
+    env.Append(CPPFLAGS=['-DWINVER=%s' % env['target_win_version'], '-D_WIN32_WINNT=%s' % env['target_win_version']])
     env.Append(LIBS=['mingw32', 'opengl32', 'dsound', 'ole32', 'd3d9', 'winmm', 'gdi32', 'iphlpapi', 'shlwapi', 'wsock32', 'ws2_32', 'kernel32', 'oleaut32', 'dinput8', 'dxguid', 'ksuser', 'imm32', 'bcrypt', 'avrt', 'uuid'])
 
     env.Append(CPPFLAGS=['-DMINGW_ENABLED'])
diff --git a/platform/x11/detect.py b/platform/x11/detect.py
index 94a87a7c90..1905b035e6 100644
--- a/platform/x11/detect.py
+++ b/platform/x11/detect.py
@@ -98,9 +98,10 @@ def configure(env):
 
     elif (env["target"] == "release_debug"):
         if (env["optimize"] == "speed"): #optimize for speed (default)
-            env.Prepend(CCFLAGS=['-O2', '-DDEBUG_ENABLED'])
+            env.Prepend(CCFLAGS=['-O2'])
         else: #optimize for size
-            env.Prepend(CCFLAGS=['-Os', '-DDEBUG_ENABLED'])
+            env.Prepend(CCFLAGS=['-Os'])
+        env.Prepend(CPPFLAGS=['-DDEBUG_ENABLED'])
 
         if (env["debug_symbols"] == "yes"):
             env.Prepend(CCFLAGS=['-g1'])
@@ -108,7 +109,8 @@ def configure(env):
             env.Prepend(CCFLAGS=['-g2'])
 
     elif (env["target"] == "debug"):
-        env.Prepend(CCFLAGS=['-g3', '-DDEBUG_ENABLED', '-DDEBUG_MEMORY_ENABLED'])
+        env.Prepend(CCFLAGS=['-g3'])
+        env.Prepend(CPPFLAGS=['-DDEBUG_ENABLED', '-DDEBUG_MEMORY_ENABLED'])
         env.Append(LINKFLAGS=['-rdynamic'])
 
     ## Architecture
@@ -315,10 +317,10 @@ def configure(env):
     ## Cross-compilation
 
     if (is64 and env["bits"] == "32"):
-        env.Append(CPPFLAGS=['-m32'])
+        env.Append(CCFLAGS=['-m32'])
         env.Append(LINKFLAGS=['-m32', '-L/usr/lib/i386-linux-gnu'])
     elif (not is64 and env["bits"] == "64"):
-        env.Append(CPPFLAGS=['-m64'])
+        env.Append(CCFLAGS=['-m64'])
         env.Append(LINKFLAGS=['-m64', '-L/usr/lib/i686-linux-gnu'])
 
     # Link those statically for portability