Pass self to lock methods.

This avoids frequent recomputation of
Thread::Current/pthread_getspecific.

Also add a futex based reader/writer mutex that is disabled.

Change-Id: I118fdb99ef1d1c4bfda6446ba3a0d8b6ab31eaee
diff --git a/src/compiler.h b/src/compiler.h
index a2cc317..c5f19f7 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -27,6 +27,7 @@
 #include "dex_file.h"
 #include "instruction_set.h"
 #include "invoke_type.h"
+#include "mutex.h"
 #include "oat_file.h"
 #include "object.h"
 #include "runtime.h"