Fix the usual build hanging issue by using -o (overwrite without prompting) option with unzip

This should fix the common problem when googlelogin-client and google-framework are both included
diff --git a/core/definitions.mk b/core/definitions.mk
index f3382c3..eccdfc9 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -1224,7 +1224,7 @@
       echo Missing file $$f; \
       exit 1; \
     fi; \
-    unzip -q $$f -d $(2); \
+    unzip -qo $$f -d $(2); \
     (cd $(2) && rm -rf META-INF); \
   done
 endef