From af4ac3dc852647e5ea41be5ffc387be591978aee Mon Sep 17 00:00:00 2001
From: Paul Eggert <address@hidden>
Date: Thu, 18 May 2017 20:27:11 -0700
Subject: [PATCH 3/4] Port --enable-gcc-warnings to clang 3.9.1

* configure.ac (WERROR_CFLAGS): Omit -Wdouble-promotion if clang.
Problem reported by Philipp Stephani in:
http://lists.gnu.org/archive/html/emacs-devel/2017-05/msg00495.html
---
 configure.ac | 1 +
 1 file changed, 1 insertion(+)

diff --git a/configure.ac b/configure.ac
index 34b75a7..03542a6 100644
--- a/configure.ac
+++ b/configure.ac
@@ -963,6 +963,7 @@ AC_DEFUN
 
   if test $emacs_cv_clang = yes; then
     nw="$nw -Wcast-align"
+    nw="$nw -Wdouble-promotion"
   fi
 
   # This causes too much noise in the MinGW build
-- 
2.7.4