Add support for GameMaker Studio constants about glsl-optimizer HOT 2 CLOSED

uniform sampler2D gm_BaseTexture;

uniform bool gm_PS_FogEnabled;
uniform vec4 gm_FogColour;
uniform bool gm_AlphaTestEnabled;
uniform float gm_AlphaRefValue;

from glsl-optimizer.

I'm not sure what is the request or why. Glsl Optimizer just takes an input GLSL shader, and writes an output GLSL (or Metal) shader. If your shader has a thing like uniform sampler2D gm_BaseTexture in there, then it's there. What special treatment they should get that does not work today?

from glsl-optimizer.