[check] Quieten output during checking headers-standalone

Remove the duplication of the compile line and enable shave to replace it
entirely with a "CHECK $header". This should make errors more obvious.

build/shave.in

@@ -69,6 +69,9 @@ lt_unmangle "$lt_output"
 output=$last_result
 
 if test -z $V; then
+    if test $output = "/dev/null"; then
+	pass_through=1
+    fi
     if test $pass_through -eq 0; then
         echo "$Q$output"
     fi

src/Makefile.am.analysis

@@ -23,7 +23,7 @@ uno:
 headers-standalone: $(enabled_cairo_headers) $(enabled_cairo_private)
 	@echo Checking that enabled public/private headers can be compiled standalone
 	@status=true; for f in $(enabled_cairo_headers) $(enabled_cairo_private); do \
-		echo $(COMPILE) -o /dev/null $(srcdir)/$$f; \
+		echo "  CHECK $$f"; \
 		$(COMPILE) -o /dev/null $(srcdir)/$$f || status=false; \
 	done; $$status
 	@touch $@