Quiet if the target is already linked the same source

ext/extmk.rb

@@ -607,7 +607,7 @@ CP_R = #{config_string('CP')} -r
 
 gemlib = $(TARGET_TOPDIR)/gems/$(gem)/lib
 gemlib:#{%{ $(gemlib)\n$(gemlib): $(gem_srcdir)/lib} if $nmake}
-	$(Q) #{@inplace ? '$(NULLCMD) ' : ''}$(RUBY) $(top_srcdir)/tool/ln_sr.rb -f -T $(gem_srcdir)/lib $(gemlib)
+	$(Q) #{@inplace ? '$(NULLCMD) ' : ''}$(RUBY) $(top_srcdir)/tool/ln_sr.rb -q -f -T $(gem_srcdir)/lib $(gemlib)
 
 clean-gemlib:
 	$(Q) $(#{@inplace ? 'NULLCMD' : 'RM_RF'}) $(gemlib)

tool/ln_sr.rb

@@ -3,6 +3,7 @@
 target_directory = true
 noop = false
 force = false
+quiet = false
 
 until ARGV.empty?
   case ARGV[0]
@@ -12,6 +13,8 @@ until ARGV.empty?
     force = true
   when '-T'
     target_directory = false
+  when '-q'
+    quiet = true
   else
     break
   end
@@ -114,6 +117,9 @@ unless respond_to?(:ln_sr)
 end
 
 if File.respond_to?(:symlink)
+  if quiet and File.identical?(src, dest)
+    exit
+  end
   begin
     ln_sr(src, dest, verbose: true, target_directory: target_directory, force: force, noop: noop)
   rescue NotImplementedError, Errno::EPERM, Errno::EACCES