I wanted to try some optimization code and to test them on my old Thinkpad X61 Tablet on which Unvanquished was running at 0.52.0 time (slow but running), and then the engine reported failing to compile the generic shader:

Warn: Compile log:
0:44(20): error: bit-wise operations are forbidden in GLSL 1.20 (GLSL 1.30 or GLSL ES 3.00 required)
0:44(20): error: bit-wise operations are forbidden in GLSL 1.20 (GLSL 1.30 or GLSL ES 3.00 required)

The GPU is an Intel GM965 one, that's one of the OpenGL 2.0 / GLSL 1.20 ones.

This regression was probably introduced in #479 to fix #472.

On a side note: that's also why I asked for a comment telling why the code had to be written that way, because the motivation of this specific shape of the code was not to implement something we want but to workaround something we don't want.