m4/symlink.m4

   1 # serial 6
   2 # See if we need to provide symlink replacement.
   3
   4 dnl Copyright (C) 2009-2014 Free Software Foundation, Inc.
   5 dnl This file is free software; the Free Software Foundation
   6 dnl gives unlimited permission to copy and/or distribute it,
   7 dnl with or without modifications, as long as this notice is preserved.
   8
   9 # Written by Eric Blake.
  10
  11 AC_DEFUN([gl_FUNC_SYMLINK],
  12 [
  13   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
  14   AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
  15   AC_CHECK_FUNCS_ONCE([symlink])
  16   dnl The best we can do on mingw is provide a dummy that always fails, so
  17   dnl that compilation can proceed with fewer ifdefs.  On FreeBSD 7.2, AIX 7.1,
  18   dnl and Solaris 9, we want to fix a bug with trailing slash handling.
  19   if test $ac_cv_func_symlink = no; then
  20     HAVE_SYMLINK=0
  21   else
  22     AC_CACHE_CHECK([whether symlink handles trailing slash correctly],
  23       [gl_cv_func_symlink_works],
  24       [AC_RUN_IFELSE(
  25          [AC_LANG_PROGRAM(
  26            [[#include <unistd.h>
  27            ]],
  28            [[int result = 0;
  29              if (!symlink ("a", "conftest.link/"))
  30                result |= 1;
  31              if (symlink ("conftest.f", "conftest.lnk2"))
  32                result |= 2;
  33              else if (!symlink ("a", "conftest.lnk2/"))
  34                result |= 4;
  35              return result;
  36            ]])],
  37          [gl_cv_func_symlink_works=yes], [gl_cv_func_symlink_works=no],
  38          [case "$host_os" in
  39                     # Guess yes on glibc systems.
  40             *-gnu*) gl_cv_func_symlink_works="guessing yes" ;;
  41                     # If we don't know, assume the worst.
  42             *)      gl_cv_func_symlink_works="guessing no" ;;
  43           esac
  44          ])
  45       rm -f conftest.f conftest.link conftest.lnk2])
  46     case "$gl_cv_func_symlink_works" in
  47       *yes) ;;
  48       *)
  49         REPLACE_SYMLINK=1
  50         ;;
  51     esac
  52   fi
  53 ])