glsl: Parse 0 as a preprocessor INTCONSTANT
glsl: Parse 0 as a preprocessor INTCONSTANT

This allows a more reasonable error message for '#version 0' of

    0:1(10): error: GLSL 0.00 is not supported. Supported versions are: 1.10, 1.20, 1.30, 1.00 ES, 3.00 ES, 3.10 ES, and 3.20 ES

instead of

    0:1(10): error: syntax error, unexpected $undefined, expecting INTCONSTANT

Signed-off-by: Ian Romanick <2b237cafb16dc45038e85df6c85e74e6d899eba9@intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=97420
Reviewed-by: Nicolai Hähnle <0d0be6cf5ad662651be2dc5dfd44aa2b09d4c1cc@amd.com>
Cc: 59f39c0db42d4479a46b02d4d2bc11120e37bb44@lists.freedesktop.org
Cc: Juan A. Suarez Romero <af79b5692270b306571bb1d8bbe0285ae3ac93d9@igalia.com>
Cc: Karol Herbst <eb05087310153da9a40ae6684203db614cfcccf7@gmail.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler