diff --git a/js/src/Makefile b/js/src/Makefile
index c243a39371a..15ae082b902 100644
--- a/js/src/Makefile
+++ b/js/src/Makefile
@@ -22,6 +22,8 @@ ifdef MOZ_OJI
 DIRS = liveconnect
 endif
 
+DIRS	+=	fdlibm
+
 LIBRARY_NAME	= js
 
 ifeq ($(subst /,_,$(shell uname -s)),OS2)
@@ -211,8 +213,19 @@ else
 	$(CC) -o $@ -c $(CFLAGS) $<
 endif
 
+# ripped from mozilla/config/rules.mk
 $(FDLIBM_LIBRARY):
-	cd fdlibm; $(MAKE)
+		@if test -d fdlibm; then				\
+			set -e;					\
+			set $(EXIT_ON_ERROR);			\
+			echo "cd fdlibm; $(MAKE) $(OBJDIR)/$(@F)";		\
+			oldDir=`pwd`;				\
+			cd fdlibm; $(MAKE) $(OBJDIR)/$(@F); cd $$oldDir;	\
+			set +e;					\
+		else						\
+			echo "Error - directory fdlibm does not exit...";	\
+		fi;						\
+		$(CLICK_STOPWATCH);
 
 # this requires clobbering and recompiling with XCFLAGS=-DJSFILE
 js: