Build system tweaks for Valgrind.

Added LOCAL_NO_CRT to enable building executables that do not link
to the C runtime library.

Removed support for LOCAL_MODULE_SUBDIR since it was broken
and unused.  (Was going to use it but ended up using LOCAL_MODULE_PATH
instead.)

Change-Id: I3b6f5ab7e5ae6aaa7119899adccece2b4ab1cbb3
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index ca70c55..0d2e215 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -105,6 +105,7 @@
 LOCAL_DEX_PREOPT:=
 LOCAL_PROTOC_OPTIMIZE_TYPE:= # lite(default),micro,full
 LOCAL_PROTOC_FLAGS:=
+LOCAL_NO_CRT:=
 
 # Trim MAKEFILE_LIST so that $(call my-dir) doesn't need to
 # iterate over thousands of entries every time.