Support Clang as a `cross-tool' and use it under Android.

[mdw-cross] / tools / cross-clang

diff --git a/tools/cross-clang b/tools/cross-clang
new file mode 120000 (symlink)
index 0000000..ee678c4
--- /dev/null
+++ b/tools/cross-clang
@@ -0,0 +1 @@
+../bin/crosstool
\ No newline at end of file