gcc -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"test.d" -MT"test.d" -o"test.o" "../test.c"
../test.c:9:1: warning: "GL_TRUE" redefined
In file included from /System/Library/Frameworks/OpenGL.framework/Headers/OpenGL.h:10,
/System/Library/Frameworks/OpenGL.framework/Headers/gl.h:173:1: warning: this is the location of the previous definition
I see an entry in the problems view which looks OK, except the path is blank:
Description Resource Path Location Type
/System/Library/Frameworks/OpenGL.framework/Headers/gl.h this is the location of the previous definition test_c line 173 C/C++ Problem
So it seems to deal with this situation fairly gracefully.