Some tweaks to the valgrind makefile code

This reenables valgrinding of the compiler and prints a message
when the user _is_ valgrinding

Author: brson

Makefile.in

@@ -144,8 +144,9 @@ ifneq ($(wildcard $(CFG_GIT_DIR)),)
 endif
 endif
 
-ifdef CFG_DISABLE_VALGRIND
-  $(info cfg: disabling valgrind (CFG_DISABLE_VALGRIND))
+ifdef CFG_ENABLE_VALGRIND
+  $(info cfg: enabling valgrind (CFG_ENABLE_VALGRIND))
+else
   CFG_VALGRIND :=
 endif
 ifdef CFG_BAD_VALGRIND
@@ -368,7 +369,7 @@ endif
 
 STAGE$(1)_T_$(2)_H_$(3) := 						\
 	$$(Q)$$(call CFG_RUN_TARG,$(1),				\
-## 		$$(CFG_VALGRIND_COMPILE$(1)) 			\
+		$$(CFG_VALGRIND_COMPILE$(1)) 			\
 		$$(HBIN$(1)_H_$(3))/rustc$$(X)			\
 		--cfg $$(CFGFLAG$(1)_T_$(2)_H_$(3))			\
 		$$(CFG_RUSTC_FLAGS) $$(EXTRAFLAGS_STAGE$(1)) --target=$(2))