gcc: changed to use pkgprefix for determining the path of the build requirements properly

base/gcc/gcc.conf

@@ -131,10 +131,11 @@ if atstage toolchain; then
 	var_append confopt " " "--disable-libquadmath"
 
 	# use the native libraries we build in the toolchain directory
-	var_append extraconfopt ' ' "--with-gmp=$root"
-	var_append extraconfopt ' ' "--with-mpfr=$root --with-mpfr-lib=$root/$libdir"
-	var_append extraconfopt ' ' "--with-ppl=$root"
-	var_append extraconfopt ' ' "--with-cloog=$root"
+	var_append extraconfopt ' ' "--with-gmp=$( pkgprefix -r gmp )"
+	var_append extraconfopt ' ' "--with-mpfr=$( pkgprefix -r mpfr )"
+	var_append extraconfopt ' ' "--with-mpfr-lib=$( pkgprefix -r libdir mpfr )"
+	var_append extraconfopt ' ' "--with-ppl=$( pkgprefix -r ppl )"
+	var_append extraconfopt ' ' "--with-cloog=$( pkgprefix -r cloog )"
 	export LDFLAGS="-Wl,-rpath,${root}${libdir}"
 fi