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/TARGET_linux-x86.mk b/core/combo/TARGET_linux-x86.mk
index 25f8aec..350d25c 100644
--- a/core/combo/TARGET_linux-x86.mk
+++ b/core/combo/TARGET_linux-x86.mk
@@ -127,7 +127,9 @@
 	-Wl,--whole-archive \
 	$(call normalize-target-libraries,$(PRIVATE_ALL_WHOLE_STATIC_LIBRARIES)) \
 	-Wl,--no-whole-archive \
+	$(if $(PRIVATE_GROUP_STATIC_LIBRARIES),-Wl$(comma)--start-group) \
 	$(call normalize-target-libraries,$(PRIVATE_ALL_STATIC_LIBRARIES)) \
+	$(if $(PRIVATE_GROUP_STATIC_LIBRARIES),-Wl$(comma)--end-group) \
 	$(call normalize-target-libraries,$(PRIVATE_ALL_SHARED_LIBRARIES)) \
 	-o $@ \
 	$(PRIVATE_LDFLAGS) \
@@ -148,7 +150,9 @@
 	$(call normalize-target-libraries,$(PRIVATE_ALL_SHARED_LIBRARIES)) \
 	$(if $(filter true,$(PRIVATE_NO_CRT)),,$(TARGET_CRTBEGIN_DYNAMIC_O)) \
 	$(PRIVATE_ALL_OBJECTS) \
+	$(if $(PRIVATE_GROUP_STATIC_LIBRARIES),-Wl$(comma)--start-group) \
 	$(call normalize-target-libraries,$(PRIVATE_ALL_STATIC_LIBRARIES)) \
+	$(if $(PRIVATE_GROUP_STATIC_LIBRARIES),-Wl$(comma)--end-group) \
 	$(PRIVATE_LDFLAGS) \
 	$(TARGET_LIBGCC) \
 	$(if $(filter true,$(PRIVATE_NO_CRT)),,$(TARGET_CRTEND_O))