glsl/varying_packing: Add 64-bit integer support
glsl/varying_packing: Add 64-bit integer support

As for the double code, but using the 64-bit integer conversions.

v2 (idr): Remove some spurious u2i() and i2u() operations when packing
and unpacking, respectively, int64_t varyings.

Signed-off-by: Dave Airlie <f2295d84e358395675bc8031be58672073ae065e@redhat.com>
Reviewed-by: Ian Romanick <2b237cafb16dc45038e85df6c85e74e6d899eba9@intel.com> [v1]
Reviewed-by: Matt Turner <789b315743a28dd066a4ba1459c35951c291d8a6@gmail.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler