[build] Fix building within zircon

Change-Id: I56bfd98c6039c861223f77829e8e635bbad31a44
diff --git a/rules.mk b/rules.mk
index 2182f99..e5dc310 100644
--- a/rules.mk
+++ b/rules.mk
@@ -121,6 +121,7 @@
 $(eval MODULE := $(THIRD_PARTY_SBASE_DIR).$(1))\
 $(eval MODULE_NAME := $(1))\
 $(eval MODULE_TYPE := userapp)\
+$(eval MODULE_GROUP := misc)\
 $(eval MODULE_SRCS += $(THIRD_PARTY_SBASE_DIR)/$(1).c)\
 $(eval MODULE_STATIC_LIBS := $(THIRD_PARTY_SBASE_DIR)/libutil $(THIRD_PARTY_SBASE_DIR)/libutf)\
 $(eval MODULE_LIBS := $(THIRD_PARTY_SBASE_LIBS))\