Support for the .glsl extension

[eliemichel]

Using shader.glsl as input leads to Unknown input file extension. I believe using .glsl as an extension for GLSL files is not an exotic practice and should be supported. If the type of shader is needed (frag/vert/comp) this could be added as an command line argument.

[teoxoy]

Sounds like a good addition, would you be interested in contributing it?

[eliemichel]

Sure, here is a proposal: #2462

[waywardmonkeys]

This was fixed by #2462 and can be closed, I think.