glsl: Disable MSVC switch warning on a per-file basis.
glsl: Disable MSVC switch warning on a per-file basis.

This addresses

  ...\glsl_parser.cpp(...) : warning C4065: switch statement contains 'default' but no 'case' labels

This is on code generated by bison, which we have little control.

It seems useful to have this warning otherwise enabled.

Reviewed-by: Brian Paul <3cb4e1df5ec4da2c7c4af7c52cec8cf340a55a10@vmware.com>
Reviewed-by: Ian Romanick <2b237cafb16dc45038e85df6c85e74e6d899eba9@intel.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler