Makefile cosmetics

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@20410 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

subdir.mak

@@ -5,7 +5,7 @@ include $(SUBDIR)../common.mak
 LIBVERSION := $(lib$(NAME)_VERSION)
 LIBMAJOR   := $(lib$(NAME)_VERSION_MAJOR)
 
-ifeq ($(CONFIG_STATIC),yes)
+ifdef CONFIG_STATIC
 all: $(SUBDIR)$(LIBNAME)
 
 install-libs: install-lib$(NAME)-static