mesa @19.0.8: build fails on < 10.7 with glext.h:303:15: error: typedef redefinition with different types

[kencu (Ken)]

There is a longstanding issue going back to 2005 with types in mesa, I read. Jeremy has been involved in this issue for 15 years. There are some workarounds in mesa for OSX.

mesa @17.x built on 10.6 and other older systems without any trouble, and still does. mesa @19.x is failing due to this:

In file included from apple_glx_drawable.c:37:
In file included from ./apple_glx_context.h:37:
In file included from /System/Library/Frameworks/OpenGL.framework/Headers/CGLContext.h:9:
In file included from /System/Library/Frameworks/OpenGL.framework/Headers/gliDispatch.h:9:
/System/Library/Frameworks/OpenGL.framework/Headers/glext.h:303:15: error: typedef redefinition with different types ('void *' vs 'unsigned long')
typedef void *GLhandleARB;
              ^
../../../include/GL/glext.h:4094:23: note: previous definition is here
typedef unsigned long GLhandleARB;
                      ^
1 error generated.
make[4]: *** [apple_glx_drawable.lo] Error 1
In file included from apple_glx_context.c:52:
In file included from ./apple_glx_context.h:37:
In file included from /System/Library/Frameworks/OpenGL.framework/Headers/CGLContext.h:9:
In file included from /System/Library/Frameworks/OpenGL.framework/Headers/gliDispatch.h:9:
/System/Library/Frameworks/OpenGL.framework/Headers/glext.h:303:15: error: typedef redefinition with different types ('void *' vs 'unsigned long')
typedef void *GLhandleARB;
              ^
../../../include/GL/glext.h:4094:23: note: previous definition is here
typedef unsigned long GLhandleARB;
                      ^

It is not obvious to me, after several hours of poking around in the guts of the GL headers, comparing 10.6 (where it fails) to 10.7 (where it succeeds) etc what the issue is, exactly.

[kencu (Ken)]

this attempt was with clang-5.0