diff --git a/xpcom.mk b/xpcom.mk
index bbc53b630e9c3f80e555690c8859ee3c1275deca..78d7a044eec83deca5399514c5a06b92429d8e4e 100644
--- a/xpcom.mk
+++ b/xpcom.mk
@@ -110,6 +110,7 @@ $(foreach lib,$(___LIBS),\
 $(foreach lib,$(filter-out $(GLOBAL_SEEN_XPCOM_STATIC_LIBRARIES),$(LOCAL_XPCOM_STATIC_LIBRARIES)),\
   $(eval $(TARGET_OUT_INTERMEDIATES)/STATIC_LIBRARIES/$(lib)_intermediates/export_includes: ; mkdir -p $$(@D) && touch $$@))
 GLOBAL_SEEN_XPCOM_STATIC_LIBRARIES += $(LOCAL_XPCOM_STATIC_LIBRARIES)
+GLOBAL_SEEN_XPCOM_STATIC_LIBRARIES := $(sort $(GLOBAL_SEEN_XPCOM_STATIC_LIBRARIES))
 
 LOCAL_STATIC_LIBRARIES := $(LOCAL_STATIC_LIBRARIES) $(LOCAL_XPCOM_STATIC_LIBRARIES)
 
@@ -126,6 +127,7 @@ $(foreach lib,$(___LIBS),\
 $(foreach lib,$(filter-out $(GLOBAL_SEEN_XPCOM_SHARED_LIBRARIES),$(LOCAL_XPCOM_SHARED_LIBRARIES)),\
   $(eval $(TARGET_OUT_INTERMEDIATES)/SHARED_LIBRARIES/$(lib)_intermediates/export_includes: ; mkdir -p $$(@D) && touch $$@))
 GLOBAL_SEEN_XPCOM_SHARED_LIBRARIES += $(LOCAL_XPCOM_SHARED_LIBRARIES)
+GLOBAL_SEEN_XPCOM_SHARED_LIBRARIES := $(sort $(GLOBAL_SEEN_XPCOM_SHARED_LIBRARIES))
 
 LOCAL_SHARED_LIBRARIES := $(LOCAL_SHARED_LIBRARIES) $(LOCAL_XPCOM_SHARED_LIBRARIES)