xbps-src: create a cc/g++ wrapper to drop -I/usr/include -L/usr/lib in cross.

I'm tired of wasting extra time to fix software to remove standard include/lib dirs.

common/wrappers/cc

@@ -0,0 +1,14 @@
+#!/bin/sh
+
+# compiler wrapper to get rid of -I/usr/include and -L/usr/lib, that fucks up
+# cross compilation badly.
+MYARGS=
+
+for i in $@; do
+	if [ $i = "-L/usr/lib" -o $i = "-I/usr/include" ]; then
+		continue
+	else
+		MYARGS+="$i "
+	fi
+done
+exec @BIN@ ${MYARGS}