Improve `linuxbsd` headless building, cleanup build scripts

Now the `linuxbsd` platform can be built headlessly (e.g. without X11
development libraries).

I also cleaned up some weird (old?) usages of the `env` variable which
seem to make no difference and are used nowhere else.

2 files changed, 19 insertions, 53 deletions

diff --git a/platform/linuxbsd/SCsub b/platform/linuxbsd/SCsub
index 09a432eae2..636a3c7db2 100644
--- a/platform/linuxbsd/SCsub
+++ b/platform/linuxbsd/SCsub
@@ -12,7 +12,7 @@ common_linuxbsd = [
     "freedesktop_screensaver.cpp",
 ]
 
-if "x11" in env and env["x11"]:
+if env["x11"]:
     common_linuxbsd += [
         "gl_manager_x11.cpp",
         "detect_prime_x11.cpp",
@@ -20,13 +20,13 @@ if "x11" in env and env["x11"]:
         "key_mapping_x11.cpp",
     ]
 
-if "speechd" in env and env["speechd"]:
-    common_linuxbsd.append(["speechd-so_wrap.c", "tts_linux.cpp"])
+    if env["vulkan"]:
+        common_linuxbsd.append("vulkan_context_x11.cpp")
 
-if "vulkan" in env and env["vulkan"]:
-    common_linuxbsd.append("vulkan_context_x11.cpp")
+if env["speechd"]:
+    common_linuxbsd.append(["speechd-so_wrap.c", "tts_linux.cpp"])
 
-if "udev" in env and env["udev"]:
+if env["udev"]:
     common_linuxbsd.append("libudev-so_wrap.c")
 
 prog = env.add_program("#bin/godot", ["godot_linuxbsd.cpp"] + common_linuxbsd)
diff --git a/platform/linuxbsd/detect.py b/platform/linuxbsd/detect.py
index c5aff743e0..63f0b7b3b9 100644
--- a/platform/linuxbsd/detect.py
+++ b/platform/linuxbsd/detect.py
@@ -15,47 +15,11 @@ def can_build():
     if os.name != "posix" or sys.platform == "darwin":
         return False
 
-    # Check the minimal dependencies
-    x11_error = os.system("pkg-config --version > /dev/null")
-    if x11_error:
+    pkgconf_error = os.system("pkg-config --version > /dev/null")
+    if pkgconf_error:
         print("Error: pkg-config not found. Aborting.")
         return False
 
-    x11_error = os.system("pkg-config x11 --modversion > /dev/null")
-    if x11_error:
-        print("Error: X11 libraries not found. Aborting.")
-        return False
-
-    x11_error = os.system("pkg-config xcursor --modversion > /dev/null")
-    if x11_error:
-        print("Error: Xcursor library not found. Aborting.")
-        return False
-
-    x11_error = os.system("pkg-config xinerama --modversion > /dev/null")
-    if x11_error:
-        print("Error: Xinerama library not found. Aborting.")
-        return False
-
-    x11_error = os.system("pkg-config xext --modversion > /dev/null")
-    if x11_error:
-        print("Error: Xext library not found. Aborting.")
-        return False
-
-    x11_error = os.system("pkg-config xrandr --modversion > /dev/null")
-    if x11_error:
-        print("Error: XrandR library not found. Aborting.")
-        return False
-
-    x11_error = os.system("pkg-config xrender --modversion > /dev/null")
-    if x11_error:
-        print("Error: XRender library not found. Aborting.")
-        return False
-
-    x11_error = os.system("pkg-config xi --modversion > /dev/null")
-    if x11_error:
-        print("Error: Xi library not found. Aborting.")
-        return False
-
     return True
 
 
@@ -219,13 +183,14 @@ def configure(env):
 
     ## Dependencies
 
-    env.ParseConfig("pkg-config x11 --cflags --libs")
-    env.ParseConfig("pkg-config xcursor --cflags --libs")
-    env.ParseConfig("pkg-config xinerama --cflags --libs")
-    env.ParseConfig("pkg-config xext --cflags --libs")
-    env.ParseConfig("pkg-config xrandr --cflags --libs")
-    env.ParseConfig("pkg-config xrender --cflags --libs")
-    env.ParseConfig("pkg-config xi --cflags --libs")
+    if env["x11"]:
+        env.ParseConfig("pkg-config x11 --cflags --libs")
+        env.ParseConfig("pkg-config xcursor --cflags --libs")
+        env.ParseConfig("pkg-config xinerama --cflags --libs")
+        env.ParseConfig("pkg-config xext --cflags --libs")
+        env.ParseConfig("pkg-config xrandr --cflags --libs")
+        env.ParseConfig("pkg-config xrender --cflags --libs")
+        env.ParseConfig("pkg-config xi --cflags --libs")
 
     if env["touch"]:
         env.Append(CPPDEFINES=["TOUCH_ENABLED"])
@@ -381,8 +346,9 @@ def configure(env):
             # No pkgconfig file so far, hardcode expected lib name.
             env.Append(LIBS=["glslang", "SPIRV"])
 
-    env.Append(CPPDEFINES=["GLES3_ENABLED"])
-    env.ParseConfig("pkg-config gl --cflags --libs")
+    if env["opengl3"]:
+        env.Append(CPPDEFINES=["GLES3_ENABLED"])
+        env.ParseConfig("pkg-config gl --cflags --libs")
 
     env.Append(LIBS=["pthread"])