gmp: use the host g++ and the native libs at toolchain stage

develop/ppl/ppl.conf

@@ -0,0 +1,21 @@
+# --- SDE-COPYRIGHT-NOTE-BEGIN ---
+# This copyright note is auto-generated by ./scripts/Create-CopyPatch.
+#
+# Filename: package/.../ppl/ppl.conf
+# Copyright (C) 2009 The OpenSDE Project
+#
+# More information can be found in the files COPYING and README.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; version 2 of the License. A copy of the
+# GNU General Public License can be found in the file COPYING.
+# --- SDE-COPYRIGHT-NOTE-END ---
+
+# use the host g++ and the native libs we have built in tools.cross
+if atstage toolchain; then
+	export CXX=g++
+	export LDFLAGS="-Wl,-rpath,${root}${libdir}"
+	var_append extraconfopt ' ' '--with-libgmp-prefix=$root'
+	var_append extraconfopt ' ' '--with-libgmpxx-prefix=$root'
+fi