Add LOCAL_GROUP_STATIC_LIBRARIES

Set LOCAL_GROUP_STATIC_LIBRARIES := true to group the static libraries,
in case we need gcc flags "-Wl,--start-group" and "-Wl,--end-group" to
fix circular references.

Change-Id: I03c4901670112fcdd2bb0fe660b6924e5776fcf8
diff --git a/core/combo/HOST_darwin-x86.mk b/core/combo/HOST_darwin-x86.mk
index b829108..544a29e 100644
--- a/core/combo/HOST_darwin-x86.mk
+++ b/core/combo/HOST_darwin-x86.mk
@@ -66,7 +66,9 @@
         $(PRIVATE_ALL_OBJECTS) \
         $(call normalize-host-libraries,$(PRIVATE_ALL_SHARED_LIBRARIES)) \
         $(call normalize-host-libraries,$(PRIVATE_ALL_WHOLE_STATIC_LIBRARIES)) \
+        $(if $(PRIVATE_GROUP_STATIC_LIBRARIES),-Wl$(comma)--start-group) \
         $(call normalize-host-libraries,$(PRIVATE_ALL_STATIC_LIBRARIES)) \
+        $(if $(PRIVATE_GROUP_STATIC_LIBRARIES),-Wl$(comma)--end-group) \
         $(PRIVATE_LDLIBS) \
         -o $@ \
         $(PRIVATE_LDFLAGS) \
@@ -82,7 +84,9 @@
         $(call normalize-host-libraries,$(PRIVATE_ALL_SHARED_LIBRARIES)) \
         $(PRIVATE_ALL_OBJECTS) \
         $(call normalize-host-libraries,$(PRIVATE_ALL_WHOLE_STATIC_LIBRARIES)) \
+        $(if $(PRIVATE_GROUP_STATIC_LIBRARIES),-Wl$(comma)--start-group) \
         $(call normalize-host-libraries,$(PRIVATE_ALL_STATIC_LIBRARIES)) \
+        $(if $(PRIVATE_GROUP_STATIC_LIBRARIES),-Wl$(comma)--end-group) \
         $(PRIVATE_LDFLAGS) \
         $(PRIVATE_LDLIBS) \
         $(HOST_LIBGCC)