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.

1 files changed, 1 insertions, 1 deletions

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()