libmpc: changed to use pkgprefix to determine libdir and includedir of gmp at toolchain stage

scientific/libmpc/libmpc.conf

@@ -2,7 +2,7 @@
 # This copyright note is auto-generated by ./scripts/Create-CopyPatch.
 #
 # Filename: package/.../libmpc/libmpc.conf
-# Copyright (C) 2010 The OpenSDE Project
+# Copyright (C) 2010 - 2012 The OpenSDE Project
 #
 # More information can be found in the files COPYING and README.
 #
@@ -14,7 +14,7 @@
 
 # help configure to find the native gmp we built in the toolchain directory
 if atstage toolchain; then
-        var_append extraconfopt ' ' "--with-gmp-include=$root/$includedir" 
-        var_append extraconfopt ' ' "--with-gmp-lib=$root/$libdir"
+        var_append extraconfopt ' ' "--with-gmp-include=$( pkgprefix -r includedir gmp )"
+        var_append extraconfopt ' ' "--with-gmp-lib=$( pkgprefix -r libdir gmp )"
         var_append extraconfopt ' ' "--enable-shared=no"
 fi