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>

# uintmax_t.m4 serial 12
dnl Copyright (C) 1997-2004, 2007-2014 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.

dnl From Paul Eggert.

AC_PREREQ([2.13])

# Define uintmax_t to 'unsigned long' or 'unsigned long long'
# if it is not already defined in <stdint.h> or <inttypes.h>.

AC_DEFUN([gl_AC_TYPE_UINTMAX_T],
[
  AC_REQUIRE([gl_AC_HEADER_INTTYPES_H])
  AC_REQUIRE([gl_AC_HEADER_STDINT_H])
  if test $gl_cv_header_inttypes_h = no && test $gl_cv_header_stdint_h = no; then
    AC_REQUIRE([AC_TYPE_UNSIGNED_LONG_LONG_INT])
    test $ac_cv_type_unsigned_long_long_int = yes \
      && ac_type='unsigned long long' \
      || ac_type='unsigned long'
    AC_DEFINE_UNQUOTED([uintmax_t], [$ac_type],
      [Define to unsigned long or unsigned long long
       if <stdint.h> and <inttypes.h> don't define.])
  else
    AC_DEFINE([HAVE_UINTMAX_T], [1],
      [Define if you have the 'uintmax_t' type in <stdint.h> or <inttypes.h>.])
  fi
])