Add xcb and peflags to the cleaning target

extras/contrib/src/Makefile

@@ -2577,6 +2577,10 @@ xcb-util: xcb-util-$(XCB_UTIL_VERSION).tar.bz2
 	cd $< && make install
 	touch $@
 
+CLEAN_FILES += .xcb-util .xcb
+CLEAN_PKG += xcb-util xcb
+DISTCLEAN_PKG += xcb-util-$(XCB_UTIL_VERSION).tar.bz2 libxcb-$(XCB_VERSION).tar.bz2
+
 # ***************************************************************************
 # Peflags utility (Windows only)
 # ***************************************************************************
@@ -2591,7 +2595,8 @@ peflags/peflags.c:
 	cd peflags && install ./peflags $(PREFIX)/bin
 	touch $@
 
-CLEAN_PKG +=peflags
+CLEAN_PKG += peflags
+CLEAN_FILES += .peflags
 # ***************************************************************************
 # Some cleaning
 # ***************************************************************************