Remove EXTRA_CFLAGS.

(cherry picked from commit 9491389baf61f2dc509a499bf52afa73be94e80f)

CMakeLists.txt

@@ -2767,8 +2767,6 @@ elseif(PSP)
 
 elseif(PS2)
   sdl_compile_definitions(PRIVATE "PS2" "__PS2__")
-  sdl_include_directories(PRIVATE SYSTEM "$ENV{PS2SDK}/ports/include" "$ENV{PS2DEV}/gsKit/include")
-  target_include_directories(SDL_uclibc PRIVATE "$ENV{PS2SDK}/ports/include" "$ENV{PS2DEV}/gsKit/include")
 
   sdl_glob_sources("${SDL3_SOURCE_DIR}/src/main/ps2/*.c")