From bf19b4da725deff1f109478e4f577b54e09d08e7 Mon Sep 17 00:00:00 2001
From: Ray Donnelly <mingw.android@gmail.com>
Date: Tue, 6 Aug 2013 13:03:22 +0100
Subject: [PATCH] MinGW-w64 build fix (lacks ffs declaration)

Define ffs as __builtin_ffs if ffs is not declared but
__builtin_ffs is declared.

This problem only happens at -O0 as one of the optimization
passes substitutes ffs for __builtin_ffs.

Signed-off-by: Ray Donnelly <mingw.android@gmail.com>
Signed-off-by: Sven Verdoolaege <skimo@kotnet.org>
---
 configure.ac      | 2 ++
 isl_config_post.h | 4 ++++
 isl_hash.c        | 1 +
 3 files changed, 7 insertions(+)

diff --git a/configure.ac b/configure.ac
index 8bfeded2..437146dd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -104,6 +104,8 @@ if test $need_normalized_gcdext = true; then
 AC_DEFINE([GMP_NORMALIZE_GCDEXT], [],
 	[result of mpz_gcdext needs to be normalized])
 fi
+AC_CHECK_DECLS(ffs,[],[],[#include <strings.h>])
+AC_CHECK_DECLS(__builtin_ffs,[],[],[])
 
 AX_SUBMODULE(piplib,no|system|build,no)
 
diff --git a/isl_config_post.h b/isl_config_post.h
index 86a094df..a9cdda34 100644
--- a/isl_config_post.h
+++ b/isl_config_post.h
@@ -1,3 +1,7 @@
 #ifndef HAVE___ATTRIBUTE__
 #define __attribute__(x)
 #endif
+
+#if (HAVE_DECL_FFS==0) && (HAVE_DECL___BUILTIN_FFS==1)
+#define ffs __builtin_ffs
+#endif
diff --git a/isl_hash.c b/isl_hash.c
index 7b96c51c..bd75a0d4 100644
--- a/isl_hash.c
+++ b/isl_hash.c
@@ -11,6 +11,7 @@
 #include <strings.h>
 #include <isl/hash.h>
 #include <isl/ctx.h>
+#include "isl_config.h"
 
 uint32_t isl_hash_string(uint32_t hash, const char *s)
 {
-- 
2.11.4.GIT