shared-mime-info: create post-install-hook stamp file

Ensures that the hook isn't run every time. Also use the real stamp
file from the host build instead of host-share-mime-info as dependency,
as otherwise the target is always considered out-of-date.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/shared-mime-info/shared-mime-info.mk

@@ -66,6 +66,7 @@ host-shared-mime-info-dirclean:
 	rm -rf $(SHARED_MIME_INFO_HOST_DIR)
 
 # update the shared-mime-info database in the target
-$(SHARED_MIME_INFO_HOOK_POST_INSTALL): host-shared-mime-info
+$(SHARED_MIME_INFO_HOOK_POST_INSTALL): $(STAMP_DIR)/host_shared-mime-info_installed
 	$(SHARED_MIME_INFO_HOST_BINARY) $(STAGING_DIR)/usr/share/mime
 	$(INSTALL) -D $(STAGING_DIR)/usr/share/mime/mime.cache $(TARGET_DIR)/usr/share/mime/mime.cache
+	touch $@