From 739cdc82b5325402231f3f5e1a38f681fcbd1db2 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Tue, 15 Mar 2016 09:34:11 -0700
Subject: [PATCH] Also try clang
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Problem reported by Václav Zeman in:
http://lists.gnu.org/archive/html/autoconf/2012-10/msg00000.html
* lib/autoconf/c.m4 (AC_PROG_CC, AC_PROG_OBJC): Also try clang.
(AC_PROG_CXX): Also try clang++.
These are at the end of the existing lists, to avoid compatibility
issues in older installations.
---
 lib/autoconf/c.m4 | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/lib/autoconf/c.m4 b/lib/autoconf/c.m4
index 933955f1..9a9fbd3b 100644
--- a/lib/autoconf/c.m4
+++ b/lib/autoconf/c.m4
@@ -457,6 +457,9 @@ fi
 if test -z "$CC"; then
   AC_CHECK_TOOLS(CC, cl.exe)
 fi
+if test -z "$CC"; then
+  AC_CHECK_TOOL(CC, clang)
+fi
 ])
 
 test -z "$CC" && AC_MSG_FAILURE([no acceptable C compiler found in \$PATH])
@@ -704,7 +707,7 @@ if test -z "$CXX"; then
   else
     AC_CHECK_TOOLS(CXX,
 		   [m4_default([$1],
-			       [g++ c++ gpp aCC CC cxx cc++ cl.exe FCC KCC RCC xlC_r xlC])],
+			       [g++ c++ gpp aCC CC cxx cc++ cl.exe FCC KCC RCC xlC_r xlC clang++])],
 		   g++)
   fi
 fi
@@ -883,7 +886,7 @@ _AC_ARG_VAR_LIBS()dnl
 _AC_ARG_VAR_CPPFLAGS()dnl
 _AC_ARG_VAR_PRECIOUS([OBJC])dnl
 AC_CHECK_TOOLS(OBJC,
-	       [m4_default([$1], [gcc objcc objc cc CC])],
+	       [m4_default([$1], [gcc objcc objc cc CC clang])],
 	       gcc)
 # Provide some information about the compiler.
 _AS_ECHO_LOG([checking for _AC_LANG compiler version])
-- 
2.11.4.GIT