Add an early arm toolchain

This isn't fully functionnal yet

wrappers/armv7-w64-mingw32-clang

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+$DIR/clang -target armv7-windows-gnu "$@"

wrappers/armv7-w64-mingw32-clang++

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+$DIR/clang++ -target armv7-windows-gnu "$@"