>From 2afc250c6fae929b95e8b8915b17379cd9f2e450 Mon Sep 17 00:00:00 2001
From: Bruno Haible <address@hidden>
Date: Sun, 13 May 2018 16:13:27 +0200
Subject: [PATCH 5/9] ffs: Fix compilation error on Android.

* m4/ffs.m4 (gl_FUNC_FFS): Use AC_LINK_IFELSE instead of AC_CHECK_FUNC.
---
 ChangeLog |  5 +++++
 m4/ffs.m4 | 19 ++++++++++++++++---
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 181a08c..3943da8 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,10 @@
 2018-05-13  Bruno Haible  <address@hidden>
 
+	ffs: Fix compilation error on Android.
+	* m4/ffs.m4 (gl_FUNC_FFS): Use AC_LINK_IFELSE instead of AC_CHECK_FUNC.
+
+2018-05-13  Bruno Haible  <address@hidden>
+
 	mkfifo: Fix compilation error on Android.
 	* m4/mkfifo.m4 (gl_FUNC_MKFIFO): Use AC_LINK_IFELSE instead of
 	AC_CHECK_FUNC.
diff --git a/m4/ffs.m4 b/m4/ffs.m4
index 252e6f6..78b13ee 100644
--- a/m4/ffs.m4
+++ b/m4/ffs.m4
@@ -1,4 +1,4 @@
-# ffs.m4 serial 2
+# ffs.m4 serial 3
 dnl Copyright (C) 2011-2018 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -7,8 +7,21 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_FFS],
 [
   AC_REQUIRE([gl_HEADER_STRINGS_H_DEFAULTS])
-  AC_CHECK_FUNCS_ONCE([ffs])
-  if test $ac_cv_func_ffs = no; then
+
+  dnl We can't use AC_CHECK_FUNC here, because ffs() is defined as a
+  dnl static inline function when compiling for Android 4.2 or older.
+  AC_CACHE_CHECK([for ffs], [gl_cv_func_ffs],
+    [AC_LINK_IFELSE(
+       [AC_LANG_PROGRAM(
+          [[#include <strings.h>
+            int x;
+          ]],
+          [[return ffs(x);]])
+       ],
+       [gl_cv_func_ffs=yes],
+       [gl_cv_func_ffs=no])
+    ])
+  if test $gl_cv_func_ffs = no; then
     HAVE_FFS=0
   fi
 ])
-- 
2.7.4