configure.in: _setjmp only if _longjmp is found

* configure.in: do not check _setjmp unless _longjmp is available,
  so that configure results will not be changed by cache.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49804 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Mon Mar  2 15:36:10 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* configure.in: do not check _setjmp unless _longjmp is available,
+	  so that configure results will not be changed by cache.
+
 Mon Mar  2 14:44:56 2015  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* configure.in (RUBY_REPLACE_TYPE): restore unsigned type from

configure.in

@@ -2067,6 +2067,8 @@ AC_FUNC_FORK
 
 AC_CHECK_FUNCS(__syscall)
 AC_CHECK_FUNCS(_longjmp)		# used for AC_ARG_WITH(setjmp-type)
+# we don't use _setjmp if _longjmp doesn't exist.
+test x$ac_cv_func__longjmp = xno && ac_cv_func__setjmp=no
 AC_CHECK_FUNCS(_setjmp)			# used for AC_ARG_WITH(setjmp-type)
 AC_CHECK_FUNCS(_setjmpex)		# used for AC_ARG_WITH(setjmp-type)
 AC_CHECK_FUNCS(atan2l atan2f)
@@ -2344,9 +2346,6 @@ AC_CACHE_CHECK(for __builtin_setjmp, ac_cv_func___builtin_setjmp,
     done])
 ])
 
-# we don't use _setjmp if _longjmp doesn't exist.
-test x$ac_cv_func__longjmp = xno && ac_cv_func__setjmp=no
-
 AC_DEFUN([RUBY_SETJMP_TYPE], [
 RUBY_CHECK_BUILTIN_SETJMP
 AC_MSG_CHECKING(for setjmp type)