diff --git a/mozilla/layout/base/tests/Makefile.in b/mozilla/layout/base/tests/Makefile.in
index 9233a080cae..a6dc38d7f35 100644
--- a/mozilla/layout/base/tests/Makefile.in
+++ b/mozilla/layout/base/tests/Makefile.in
@@ -22,7 +22,7 @@ VPATH		= @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
 
-LOCAL_INCLUDES = -I../src
+LOCAL_INCLUDES = -I$(srcdir)/../src
 
 CPPSRCS = \
 	TestSpaceManager.cpp \