m4: fix gl_TIMER_TIME() detection of threads on uClibc The timer_time.m4 gl_TIMER_TIME function determines which libraries need to be linked to get access to the timer function, generally -lrt for Linux systems. On platforms where threads are used, librt typically uses thread functions from libpthread. However, the test to determine whether the platform has thread or not is incorrect: it assumes that if the C library is uClibc, then threads are not available. This is actually not true: uClibc has configurable thread support, and when thread support is available, librt calls libpthread functions. This is important when static linking is used, because otherwise only -lrt is used at link time, which fails because librt calls undefined thread functions. Both -lrt and -lpthread must be passed. This problem is fixed by making the uClibc thread detection a bit smarter, thanks to the usage of the __HAS_NO_THREADS__ macro defined in <bits/uClibc_config.h>, which itself is included by <features.h>. Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Signed-off-by: Eric Blake <eblake@redhat.com>

# serial 33

# Copyright (C) 1996-1997, 1999-2007, 2009-2014 Free Software Foundation, Inc.
#
# This file is free software; the Free Software Foundation
# gives unlimited permission to copy and/or distribute it,
# with or without modifications, as long as this notice is preserved.

# Written by Jim Meyering and Paul Eggert.

AC_DEFUN([gl_FUNC_GNU_STRFTIME],
[
  gl_FUNC_STRFTIME
])

# These are the prerequisite macros for GNU's strftime.c replacement.
AC_DEFUN([gl_FUNC_STRFTIME],
[
 # This defines (or not) HAVE_TZNAME and HAVE_TM_ZONE.
 AC_REQUIRE([AC_STRUCT_TIMEZONE])

 AC_REQUIRE([gl_TM_GMTOFF])

 AC_CHECK_FUNCS_ONCE([tzset])

 AC_DEFINE([my_strftime], [nstrftime],
   [Define to the name of the strftime replacement function.])
])