This patch avoids the gcc warnings
		../pkg-config-0.23/pkg.c:872: warning: assignment discards qualifiers from pointer target type
		../pkg-config-0.23/pkg.c:878: warning: assignment discards qualifiers from pointer target type

diff -ur pkg-config-0.23.orig/pkg.c pkg-config-0.23/pkg.c
--- pkg-config-0.23.orig/pkg.c	2008-01-16 22:59:49.000000000 +0100
+++ pkg-config-0.23/pkg.c	2008-10-13 10:09:09.000000000 +0200
@@ -754,7 +754,7 @@
   GSList *conflicts_iter;
   GSList *system_dir_iter = NULL;
   int count;
-  gchar *c_include_path;
+  const gchar *c_include_path;
 
   /* Be sure we have the required fields */