main: uses casts to silence some _mesa_debug() format warnings
main: uses casts to silence some _mesa_debug() format warnings

Silences warnings with 32-bit Linux gcc builds and MinGW which doesn't
recognize the ‘t’ conversion character.

Reviewed-by: Sinclair Yeh <326bbc75ae5821d6c8d1817b260a4d8d0fdf1f63@vmware.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler