compiler: introduce a libcompiler static library

Currently it's an empty library, although it'll be used to store common
code between GLSL and NIR that is compiler specific (rather than generic
as the one in src/util).

XXX: strictly speaking we could add a python/mako parser to generate the
relevant files instead including builtin_type_macros.h in such a manner.

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Acked-by: Matt Turner <mattst88@gmail.com>
Acked-by: Jose Fonseca <jfonseca@vmware.com>
diff --git a/src/Makefile.am b/src/Makefile.am
index 0d49bcd..a0ec401 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -21,6 +21,9 @@
 
 SUBDIRS = . gtest util mapi/glapi/gen mapi
 
+# include only conditionally ?
+SUBDIRS += compiler
+
 if NEED_OPENGL_COMMON
 SUBDIRS += glsl mesa
 endif