* lib/mkmf.rb: revert r50804 because of build failure when specifying

LDFLAGS during configure, observed on Solaris with GCC 4.6.
  [Bug #11245]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@50815 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,9 @@
+Wed Jun 10 22:27:32 2015  Naohisa Goto  <ngotogenome@gmail.com>
+
+	* lib/mkmf.rb: revert r50804 because of build failure when specifying
+	  LDFLAGS during configure, observed on Solaris with GCC 4.6.
+	  [Bug #11245]
+
 Wed Jun 10 21:59:51 2015  Kazuhiro NISHIYAMA  <zn@mbf.nifty.com>
 
 	* README.ja.md: fix markup miss.

lib/mkmf.rb

@@ -98,16 +98,22 @@ module MakeMakefile
       arg, val = arg.split('=', 2)
       next unless arg
       arg.tr!('_', '-')
-      next if /\A(--)?(?:top|topsrc|src|cur)dir\z/i =~ arg
+      if arg.sub!(/^(?!--)/, '--')
+        val or next
+        arg.downcase!
+      end
+      next if /^--(?:top|topsrc|src|cur)dir$/ =~ arg
       $configure_args[arg] = val || true
-      $configure_args["--#{arg.downcase}"] = val if val and /\A--/ !~ arg
     end
     for arg in ARGV
       arg, val = arg.split('=', 2)
       next unless arg
       arg.tr!('_', '-')
+      if arg.sub!(/^(?!--)/, '--')
+        val or next
+        arg.downcase!
+      end
       $configure_args[arg] = val || true
-      $configure_args["--#{arg.downcase}"] = val if val and /\A--/ !~ arg
     end
   end