diff --git a/Makefile.in b/Makefile.in
index 003521d3a14f..217cb4a3529c 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -226,10 +226,6 @@ ifdef MOZ_LEAKY
 tier_9_dirs        += tools/leaky
 endif
 
-ifdef ENABLE_TESTS
-tier_9_dirs	+= xpcom/tests
-endif
-
 ifdef NS_TRACE_MALLOC
 tier_9_dirs	+= tools/trace-malloc
 endif
diff --git a/xpcom/Makefile.in b/xpcom/Makefile.in
index 97e1048d0ddc..fcc676b14b3e 100644
--- a/xpcom/Makefile.in
+++ b/xpcom/Makefile.in
@@ -48,6 +48,7 @@ endif
 
 ifdef ENABLE_TESTS
 DIRS		+= \
+	tests \
 	sample \
 	typelib/xpt/tests \
 	reflect/xptinfo/tests \
diff --git a/xpcom/tests/Makefile.in b/xpcom/tests/Makefile.in
index d51772b39fa4..469aa9e29148 100644
--- a/xpcom/tests/Makefile.in
+++ b/xpcom/tests/Makefile.in
@@ -32,7 +32,7 @@ ifeq ($(OS_ARCH),WINNT)
 DIRS		+= windows
 endif
 
-REQUIRES	= necko \
+REQUIRES	= \
 		  string \
 		  $(NULL)
 
@@ -64,13 +64,6 @@ SIMPLE_PROGRAMS	= $(CPPSRCS:.cpp=$(BIN_SUFFIX))
 
 include $(topsrcdir)/config/config.mk
 
-# These won't link on BSD/OS, due to multiply defined symbols.
-ifneq ($(OS_ARCH),BSD_OS)
-CPPSRCS		+= \
-		PropertiesTest.cpp \
-		$(NULL)
-endif
-
 LIBS		+= \
 		$(XPCOM_LIBS) \
 		$(NSPR_LIBS) \