diff -up x2goclient-4.0.5.0/Makefile.flags x2goclient-4.0.5.0/Makefile
--- x2goclient-4.0.5.0/Makefile.flags	2016-03-01 18:51:25.714741181 -0600
+++ x2goclient-4.0.5.0/Makefile	2016-03-01 18:51:24.331733921 -0600
@@ -37,12 +37,12 @@ build: build_man build_pluginprovider
 
 build_client:
 	$(LRELEASE_BINARY) x2goclient.pro
-	mkdir -p $(CLIENT_DIR) && cd $(CLIENT_DIR) && $(QMAKE_BINARY) QMAKE_CFLAGS="${CPPFLAGS} ${CFLAGS}" QMAKE_CXXFLAGS="${CPPFLAGS} ${CXXFLAGS}" QMAKE_LFLAGS="${LDFLAGS}" ../x2goclient.pro
+	mkdir -p $(CLIENT_DIR) && cd $(CLIENT_DIR) && $(QMAKE_BINARY) QMAKE_CFLAGS="${CPPFLAGS} ${RPM_OPT_FLAGS} ${CFLAGS}" QMAKE_CXXFLAGS="${CPPFLAGS} ${RPM_OPT_FLAGS} ${CXXFLAGS}" QMAKE_LFLAGS="${RPM_LD_FLAGS} ${LDFLAGS}" ../x2goclient.pro
 	cd $(CLIENT_DIR) && $(MAKE)
 
 build_plugin:
 	$(LRELEASE_BINARY) x2goclient.pro
-	mkdir -p $(PLUGIN_DIR) && cd $(PLUGIN_DIR) && X2GO_CLIENT_TARGET=plugin $(QMAKE_BINARY) QMAKE_CFLAGS="${CPPFLAGS} ${CFLAGS}" QMAKE_CXXFLAGS="${CPPFLAGS} ${CXXFLAGS}" QMAKE_LFLAGS="${LDFLAGS}" ../x2goclient.pro
+	mkdir -p $(PLUGIN_DIR) && cd $(PLUGIN_DIR) && X2GO_CLIENT_TARGET=plugin $(QMAKE_BINARY) QMAKE_CFLAGS="${CPPFLAGS} ${RPM_OPT_FLAGS} ${CFLAGS}" QMAKE_CXXFLAGS="${CPPFLAGS} ${RPM_OPT_FLAGS} ${CXXFLAGS}" QMAKE_LFLAGS="${RPM_LD_FLAGS} ${LDFLAGS}" ../x2goclient.pro
 	cd $(PLUGIN_DIR) && $(MAKE)
 
 build_pluginprovider: