Whitespace cleanup of all Makefiles*

- some of the %.clean rules in the test-suite Makefiles were using a single tab
  as an empty rule, dangerous! I've replaced these with the safer '@exit 0'.

CCache/Makefile.in

@@ -69,9 +69,9 @@ distclean: clean
 maintainer-clean: distclean
 	/bin/rm -f $(PACKAGE_NAME).1 web/ccache-man.html
 
-	
+
 # FIXME: To fix this, test.sh needs to be able to take ccache from the
 # installed prefix, not from the source dir.
-installcheck: 
+installcheck:
 	@echo "WARNING!  This is not really \"installcheck\" yet."
 	$(MAKE) check