From 39626559944ac960b21cc1ce3c740a0ab61b1648 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Mon, 1 Apr 2013 05:41:27 +0000
Subject: configure.in: clang check

* configure.in: should not use AC_COMPILE_IFELSE before
  AC_USE_SYSTEM_EXTENSIONS.  [Bug #8192]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@40031 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 configure.in | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/configure.in b/configure.in
index 3a9a14aa42..4c1d7353d4 100644
--- a/configure.in
+++ b/configure.in
@@ -396,12 +396,13 @@ AS_CASE(["$host_os:$build_os"],
     # clang version 1.0 (http://llvm.org/svn/llvm-project/cfe/tags/Apple/clang-23 exported)
     # Apple clang version 2.0 (tags/Apple/clang-137) (based on LLVM 2.9svn)
     # Apple clang version 2.1 (tags/Apple/clang-163.7.1) (based on LLVM 3.0svn)
-    AC_COMPILE_IFELSE([AC_LANG_PROGRAM([
+    if ! $CC -E -xc - <<SRC >/dev/null; then
 	@%:@if defined __APPLE_CC__ && defined __clang_major__ && __clang_major__ < 3
 	@%:@error premature clang
-	@%:@endif])],
-	[],
-	[AC_MSG_ERROR([clang version 3.0 or later is required])])
+	@%:@endif
+SRC
+	AC_MSG_ERROR([clang version 3.0 or later is required])
+    fi
 ])
 if test x"${build}" != x"${host}"; then
   AC_CHECK_TOOL(CC, gcc)
-- 
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