I found this a week or so ago. I tried to post to the list about it but it
didn't work. I updated my CVS copy today and the typo remains. I'm surprised no
one's done anything about it yet. The typo is in xc/xc/programs/Xserver/GL/glx/
singlesize.c on line 907.
"case GL_FOG_COORD_SOURCE:" should actually be "case GL_FOG_COORD_SRC:"
Fixed in X.Org after last Mesa merge.