diff --git a/common.mak b/common.mak
index 2ec0dffd13..1fbdf2b489 100644
--- a/common.mak
+++ b/common.mak
@@ -87,6 +87,9 @@ endef
 
 $(eval $(RULES))
 
+# Clear DIRS variable so that it is not used in other subdirectories.
+DIRS =
+
 tests: $(TESTS)
 
 -include $(DEPS)
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 63b20789a4..a9858d79aa 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -472,8 +472,6 @@ DIRS = alpha armv4l bfin i386 mlib ppc ps2 sh4 sparc
 
 include $(SUBDIR)../subdir.mak
 
-DIRS =
-
 $(SUBDIR)cpuid-test$(EXESUF): $(SUBDIR)i386/cputest.c
 $(SUBDIR)apiexample$(EXESUF): $(SUBDIR)apiexample.o $(SUBDIR)$(LIBNAME)
 $(SUBDIR)dct-test$(EXESUF): $(SUBDIR)dct-test.o fdctref.o $(SUBDIR)$(LIBNAME)