mkmf.rb: try without -ObjC option

* lib/mkmf.rb (have_framework): try without -ObjC option first as
  MacPorts GCCs do not support it.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@47010 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/mkmf.rb

@@ -1092,11 +1092,11 @@ SRC
     checking_for fw do
       src = cpp_include("#{fw}/#{header}") << "\n" "int main(void){return 0;}"
       opt = " -framework #{fw}"
-      if try_link(src, "-ObjC#{opt}", &b)
+      if try_link(src, opt, &b) or (objc = try_link(src, "-ObjC#{opt}", &b))
         $defs.push(format("-DHAVE_FRAMEWORK_%s", fw.tr_cpp))
         # TODO: non-worse way than this hack, to get rid of separating
         # option and its argument.
-        $LDFLAGS << " -ObjC" unless /(\A|\s)-ObjC(\s|\z)/ =~ $LDFLAGS
+        $LDFLAGS << " -ObjC" if objc and /(\A|\s)-ObjC(\s|\z)/ !~ $LDFLAGS
         $LIBS << opt
         true
       else

test/mkmf/test_framework.rb

@@ -26,7 +26,9 @@ class TestMkmf
 
     def test_multi_frameworks
       assert(have_framework("CoreFoundation"), mkmflog("try as Objective-C"))
-      assert(have_framework("Cocoa"), mkmflog("try as Objective-C"))
+      create_framework("MkmfTest") do |fw|
+        assert(have_framework(fw), MKMFLOG)
+      end
     end
 
     def test_empty_framework