freedreno/ir3: support glsl linking for cmdline compiler
freedreno/ir3: support glsl linking for cmdline compiler

For .vert/.frag, now multiple can be specified on the cmdline for
purposes of linking, and the last one specified is the one that is
fed into the ir3 backend (and dumped along the way if --verbose is
specified)

Without this, varyings in frag shaders would appear as undefined.

Signed-off-by: Rob Clark <6f78cdb10adbe0a7fbbf4098125a51f401c77a5f@freedesktop.org>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler