Begin filling in ARM code generator.

We can now call functions that have no arguments (and return from them too!)
diff --git a/libacc/test b/libacc/test
index be883a6..8bf33c8 100755
--- a/libacc/test
+++ b/libacc/test
@@ -1,3 +1,3 @@
 #!/bin/sh
-g++ acc.cpp -ldl -o tests/acc && tests/acc tests/otcc.c -a x86 -d tests/otcc.out && diff tests/otcc.out tests/otcc.out-orig
+g++ acc.cpp -g -ldl -o tests/acc && tests/acc tests/otcc.c -a x86 -d tests/otcc.out && diff tests/otcc.out tests/otcc.out-orig
 tests/acc tests/simplest.c