test/Test.mak: Properly define MAKE_SRCS variable

 Fix typo in d81e53c5fa "New test targets 'compile' and 'run'" commit,
 MAKE_SRCS variable was never defined.

Signed-off-by: Leonid Lisovskiy <lly.dev@gmail.com>

test/Test.mak

@@ -116,7 +116,7 @@ compile: $(COMPILE_TARGETS)
 G_TARGET_SRCS := $(addsuffix .c,$(G_TARGETS))
 U_TARGET_SRCS := $(addsuffix .c,$(U_TARGETS))
 
-$(MAKE_SRCS): Makefile $(TESTDIR)Makefile $(TESTDIR)Rules.mak $(TESTDIR)Test.mak
+MAKE_SRCS := Makefile $(TESTDIR)Makefile $(TESTDIR)Rules.mak $(TESTDIR)Test.mak
 
 $(U_TARGETS): $(U_TARGET_SRCS) $(MAKE_SRCS)
 	$(showlink)