glsl: add "in" or "out" prefix to name when flattening interface blocks
glsl: add "in" or "out" prefix to name when flattening interface blocks

This is to prevent a name conflict in tessellation shaders built-in interface
blocks.

Reviewed-by: Kenneth Graunke <bd2562f754ec92342f93f61c25d731e290a2ffa8@whitecape.org>
Reviewed-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler