gbm: remove support for GCC older than 4.1.0
gbm: remove support for GCC older than 4.1.0

Signed-off-by: Timothy Arceri <7f85c8176b2576ffafd04ac63cd29ed35ff86cb6@yahoo.com.au>
Reviewed-By: Jose Fonseca <61b5a29db2c0650f7c8510f93eece059c1b09320@vmware.com>
Reviewed-by: Ian Romanick <2b237cafb16dc45038e85df6c85e74e6d899eba9@intel.com>
Reviewed-by: Matt Turner <789b315743a28dd066a4ba1459c35951c291d8a6@gmail.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler