* configure.in: limit to "T" type for prefix of external symbols

because x86_64-w64-mingw32-gcc on Debian GNU/Linux generates the
  following symbol:
    0000000068483390 D _GLOBAL__F__conftest_external

  Approved by nobu.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@31531 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,12 @@
+Thu May 12 18:24:34 2011  Kouhei Sutou  <kou@clear-code.com>
+
+	* configure.in: limit to "T" type for prefix of external symbols
+	  because x86_64-w64-mingw32-gcc on Debian GNU/Linux generates the
+	  following symbol:
+	    0000000068483390 D _GLOBAL__F__conftest_external
+
+	  Approved by nobu.
+
 Thu May 12 14:50:52 2011  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* test/dl/test_base.rb (Fiddle::LIBC_SO): its always msvc*.dll on

configure.in

@@ -2396,7 +2396,7 @@ fi
 AC_CACHE_CHECK([for prefix of external symbols], rb_cv_symbol_prefix, [
     AC_TRY_COMPILE([extern void conftest_external(void) {}], [], [
 	rb_cv_symbol_prefix=`$NM conftest.$ac_objext |
-			     sed -n ['/.*[ 	]\([^ 	]*\)conftest_external.*/!d;s//\1/p;q']`
+			     sed -n ['/.*T[ 	]\([^ 	]*\)conftest_external.*/!d;s//\1/p;q']`
 	],
 	[rb_cv_symbol_prefix=''])
     test -n "$rb_cv_symbol_prefix" || rb_cv_symbol_prefix=NONE