osmesa: Add OSMesaColorClamp and OSMesaGetProcAddress to symbol defs.
osmesa: Add OSMesaColorClamp and OSMesaGetProcAddress to symbol defs.

Without this patch, the two symbols get an underscore prepended
and an "@4" appended when compiling with VC8.

Signed-off-by: Brian Paul <brianp@vmware.com>

(cherry picked from commit e65029e9b32ddabea0ec583c04484345b40f1557)

mcanthony/glsl-optimizer,tokyovigilante/glsl-optimizer,bkaradzic/glsl-optimizer,djreep81/glsl-optimizer,mcanthony/glsl-optimizer,zz85/glsl-optimizer,mapbox/glsl-optimizer,dellis1972/glsl-optimizer,benaadams/glsl-optimizer,tokyovigilante/glsl-optimizer,mapbox/glsl-optimizer,djreep81/glsl-optimizer,benaadams/glsl-optimizer,metora/MesaGLSLCompiler,zeux/glsl-optimizer,dellis1972/glsl-optimizer,adobe/glsl2agal,zz85/glsl-optimizer,zz85/glsl-optimizer,jbarczak/glsl-optimizer,bkaradzic/glsl-optimizer,mapbox/glsl-optimizer,dellis1972/glsl-optimizer,benaadams/glsl-optimizer,zz85/glsl-optimizer,KTXSoftware/glsl2agal,tokyovigilante/glsl-optimizer,wolf96/glsl-optimizer,wolf96/glsl-optimizer,zz85/glsl-optimizer,benaadams/glsl-optimizer,tokyovigilante/glsl-optimizer,adobe/glsl2agal,adobe/glsl2agal,bkaradzic/glsl-optimizer,jbarczak/glsl-optimizer,dellis1972/glsl-optimizer,wolf96/glsl-optimizer,wolf96/glsl-optimizer,dellis1972/glsl-optimizer,metora/MesaGLSLCompiler,bkaradzic/glsl-optimizer,jbarczak/glsl-optimizer,KTXSoftware/glsl2agal,djreep81/glsl-optimizer,zz85/glsl-optimizer,metora/MesaGLSLCompiler,djreep81/glsl-optimizer,benaadams/glsl-optimizer,mcanthony/glsl-optimizer,mapbox/glsl-optimizer,mcanthony/glsl-optimizer,zeux/glsl-optimizer,jbarczak/glsl-optimizer,zeux/glsl-optimizer,mcanthony/glsl-optimizer,zeux/glsl-optimizer,djreep81/glsl-optimizer,adobe/glsl2agal,jbarczak/glsl-optimizer,mapbox/glsl-optimizer,tokyovigilante/glsl-optimizer,adobe/glsl2agal,KTXSoftware/glsl2agal,KTXSoftware/glsl2agal,benaadams/glsl-optimizer,bkaradzic/glsl-optimizer,KTXSoftware/glsl2agal,wolf96/glsl-optimizer,zeux/glsl-optimizer