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: Ifed4ffe17003d90370c711ea6606e2b75e841dee
diff --git a/core/definitions.mk b/core/definitions.mk
index 9112af6..975b6b5 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -679,6 +679,7 @@
 @echo PRIVATE_ALL_STATIC_LIBRARIES=$(PRIVATE_ALL_STATIC_LIBRARIES);
 @echo PRIVATE_ALL_WHOLE_STATIC_LIBRARIES=$(PRIVATE_ALL_WHOLE_STATIC_LIBRARIES);
 @echo PRIVATE_ALL_OBJECTS=$(PRIVATE_ALL_OBJECTS);
+@echo PRIVATE_NO_CRT=$(PRIVATE_NO_CRT);
 endef
 
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