diff --git a/browser/components/sessionstore/src/Makefile.in b/browser/components/sessionstore/src/Makefile.in
index a8d4832f7ba..d9a410295de 100644
--- a/browser/components/sessionstore/src/Makefile.in
+++ b/browser/components/sessionstore/src/Makefile.in
@@ -8,6 +8,7 @@ srcdir    = @srcdir@
 VPATH     = @srcdir@
 
 include $(DEPTH)/config/autoconf.mk
+include $(topsrcdir)/config/config.mk
 
 EXTRA_COMPONENTS = \
   nsSessionStore.manifest \
@@ -18,24 +19,16 @@ EXTRA_PP_COMPONENTS = \
 	nsSessionStartup.js \
 	$(NULL)
 
-libs::
-	$(NSINSTALL) $(srcdir)/*.jsm $(FINAL_TARGET)/modules/sessionstore
+JS_MODULES_PATH := $(FINAL_TARGET)/modules/sessionstore
 
-SS_EXTRA_PP_JS_MODULES = \
+EXTRA_JS_MODULES := \
+  DocumentUtils.jsm \
+  SessionStorage.jsm \
+  XPathGenerator.jsm \
+  $(NULL)
+
+EXTRA_PP_JS_MODULES := \
 	SessionStore.jsm \
 	$(NULL)
 
-ifdef SS_EXTRA_PP_JS_MODULES
-libs:: $(SS_EXTRA_PP_JS_MODULES)
-ifndef NO_DIST_INSTALL
-	$(EXIT_ON_ERROR) \
-	$(NSINSTALL) -D $(FINAL_TARGET)/modules/sessionstore; \
-	for i in $^; do \
-	  dest=$(FINAL_TARGET)/modules/sessionstore/`basename $$i`; \
-	  $(RM) -f $$dest; \
-	  $(PYTHON) $(topsrcdir)/config/Preprocessor.py $(DEFINES) $(ACDEFINES) $(XULPPFLAGS) $$i > $$dest; \
-	done
-endif
-endif
-
 include $(topsrcdir)/config/rules.mk
diff --git a/config/rules.mk b/config/rules.mk
index 640894f887d..7b6d425d1cd 100644
--- a/config/rules.mk
+++ b/config/rules.mk
@@ -1385,11 +1385,14 @@ libs::
 endif
 
 ################################################################################
-# Copy each element of EXTRA_JS_MODULES to $(FINAL_TARGET)/modules
+# Copy each element of EXTRA_JS_MODULES to JS_MODULES_PATH, or
+# $(FINAL_TARGET)/modules if that isn't defined.
+JS_MODULES_PATH ?= $(FINAL_TARGET)/modules
+
 ifdef EXTRA_JS_MODULES
 libs:: $(EXTRA_JS_MODULES)
 ifndef NO_DIST_INSTALL
-	$(call install_cmd,$(IFLAGS1) $^ $(FINAL_TARGET)/modules)
+	$(call install_cmd,$(IFLAGS1) $^ $(JS_MODULES_PATH))
 endif
 
 endif
@@ -1398,9 +1401,9 @@ ifdef EXTRA_PP_JS_MODULES
 libs:: $(EXTRA_PP_JS_MODULES)
 ifndef NO_DIST_INSTALL
 	$(EXIT_ON_ERROR) \
-	$(NSINSTALL) -D $(FINAL_TARGET)/modules; \
+	$(NSINSTALL) -D $(JS_MODULES_PATH); \
 	for i in $^; do \
-	  dest=$(FINAL_TARGET)/modules/`basename $$i`; \
+	  dest=$(JS_MODULES_PATH)/`basename $$i`; \
 	  $(RM) -f $$dest; \
 	  $(PYTHON) $(topsrcdir)/config/Preprocessor.py $(DEFINES) $(ACDEFINES) $(XULPPFLAGS) $$i > $$dest; \
 	done
diff --git a/js/src/config/rules.mk b/js/src/config/rules.mk
index 640894f887d..7b6d425d1cd 100644
--- a/js/src/config/rules.mk
+++ b/js/src/config/rules.mk
@@ -1385,11 +1385,14 @@ libs::
 endif
 
 ################################################################################
-# Copy each element of EXTRA_JS_MODULES to $(FINAL_TARGET)/modules
+# Copy each element of EXTRA_JS_MODULES to JS_MODULES_PATH, or
+# $(FINAL_TARGET)/modules if that isn't defined.
+JS_MODULES_PATH ?= $(FINAL_TARGET)/modules
+
 ifdef EXTRA_JS_MODULES
 libs:: $(EXTRA_JS_MODULES)
 ifndef NO_DIST_INSTALL
-	$(call install_cmd,$(IFLAGS1) $^ $(FINAL_TARGET)/modules)
+	$(call install_cmd,$(IFLAGS1) $^ $(JS_MODULES_PATH))
 endif
 
 endif
@@ -1398,9 +1401,9 @@ ifdef EXTRA_PP_JS_MODULES
 libs:: $(EXTRA_PP_JS_MODULES)
 ifndef NO_DIST_INSTALL
 	$(EXIT_ON_ERROR) \
-	$(NSINSTALL) -D $(FINAL_TARGET)/modules; \
+	$(NSINSTALL) -D $(JS_MODULES_PATH); \
 	for i in $^; do \
-	  dest=$(FINAL_TARGET)/modules/`basename $$i`; \
+	  dest=$(JS_MODULES_PATH)/`basename $$i`; \
 	  $(RM) -f $$dest; \
 	  $(PYTHON) $(topsrcdir)/config/Preprocessor.py $(DEFINES) $(ACDEFINES) $(XULPPFLAGS) $$i > $$dest; \
 	done