diff --git a/Makefile.in b/Makefile.in
index 7a9d128d8ec3..1a65d798dc68 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -221,3 +221,5 @@ ifeq ($(OS_TARGET)_$(TARGET_XPCOM_ABI),Linux_x86-gcc3)
 scheck::
 	@relcount=`find $(DIST)/bin -name "*.so" | xargs objdump -R | grep R_386_PC32 | wc -l` && if test $$relcount -gt 0; then echo "FAILED: R_386_PC32 relocations detected in a shared library.  Did you use a system header without adding it to config/system-headers?"; exit 1; else echo "PASSED"; fi
 endif
+
+js/src/Makefile: subsrcdir := js/src
diff --git a/config/rules.mk b/config/rules.mk
index 33f3cd753a50..03647b6b9a48 100644
--- a/config/rules.mk
+++ b/config/rules.mk
@@ -1161,7 +1161,7 @@ ifndef NO_SUBMAKEFILES_RULE
 ifdef SUBMAKEFILES
 # VPATH does not work on some machines in this case, so add $(srcdir)
 $(SUBMAKEFILES): % : $(srcdir)/%.in
-	$(PERL) $(AUTOCONF_TOOLS)/make-makefile -t $(topsrcdir) -d $(DEPTH) $@
+	$(if $(subsrcdir),cd $(subsrcdir) && )$(PERL) $(AUTOCONF_TOOLS)/make-makefile -t $(topsrcdir)$(addprefix /,$(subsrcdir)) -d $(DEPTH) $(@:$(subsrcdir)/%=%)
 endif
 endif
 
diff --git a/js/src/config/rules.mk b/js/src/config/rules.mk
index 33f3cd753a50..03647b6b9a48 100644
--- a/js/src/config/rules.mk
+++ b/js/src/config/rules.mk
@@ -1161,7 +1161,7 @@ ifndef NO_SUBMAKEFILES_RULE
 ifdef SUBMAKEFILES
 # VPATH does not work on some machines in this case, so add $(srcdir)
 $(SUBMAKEFILES): % : $(srcdir)/%.in
-	$(PERL) $(AUTOCONF_TOOLS)/make-makefile -t $(topsrcdir) -d $(DEPTH) $@
+	$(if $(subsrcdir),cd $(subsrcdir) && )$(PERL) $(AUTOCONF_TOOLS)/make-makefile -t $(topsrcdir)$(addprefix /,$(subsrcdir)) -d $(DEPTH) $(@:$(subsrcdir)/%=%)
 endif
 endif