nir: move shader_enums.[ch] to compiler

This way one can reuse it in glsl, nir or other infrastructure without
pulling nir as dependency.

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Acked-by: Matt Turner <mattst88@gmail.com>
Acked-by: Jose Fonseca <jfonseca@vmware.com>

src/SConscript

@@ -5,6 +5,7 @@ if env['platform'] == 'windows':
     SConscript('getopt/SConscript')
 
 SConscript('util/SConscript')
+SConscript('compiler/SConscript')
 SConscript('glsl/SConscript')
 
 if env['hostonly']: