-# posixver.m4 serial 2
-dnl Copyright (C) 2002, 2003 Free Software Foundation, Inc.
-dnl This file is free software, distributed under the terms of the GNU
-dnl General Public License. As a special exception to the GNU General
-dnl Public License, this file may be distributed as part of a program
-dnl that contains a configuration script generated by Autoconf, under
-dnl the same distribution terms as the rest of that program.
+# posixver.m4 serial 9
+dnl Copyright (C) 2002, 2003, 2004, 2005, 2006 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.
AC_DEFUN([gl_POSIXVER],
[
- AC_CHECK_HEADERS_ONCE(unistd.h)
+ AC_LIBOBJ([posixver])
+
+ AC_REQUIRE([gl_DEFAULT_POSIX2_VERSION])
+])
+
+# Set the default level of POSIX conformance at configure-time.
+# Build with `./configure DEFAULT_POSIX2_VERSION=199209 ...' to
+# support the older version, thus preserving portability with
+# scripts that use sort +1, tail +32, etc.
+# Note however, that this breaks tools that might run commands
+# like `sort +some-file' that conform with the newer standard.
+AC_DEFUN([gl_DEFAULT_POSIX2_VERSION],
+[
+ AC_MSG_CHECKING([for desired default level of POSIX conformance])
+ gl_default_posix2_version=none-specified
+ if test -n "$ac_cv_env_DEFAULT_POSIX2_VERSION_set"; then
+ gl_default_posix2_version=$ac_cv_env_DEFAULT_POSIX2_VERSION_value
+ AC_DEFINE_UNQUOTED(DEFAULT_POSIX2_VERSION,
+ $gl_default_posix2_version,
+ [Define the default level of POSIX conformance. The value is of
+ the form YYYYMM, specifying the year and month the standard was
+ adopted. If not defined here, it defaults to the value of
+ _POSIX2_VERSION in <unistd.h>. Define to 199209 to default to
+ POSIX 1003.2-1992, which makes standard programs like `head',
+ `tail', and `sort' accept obsolete options like `+10' and
+ `-10'. Define to 200112 to default to POSIX 1003.1-2001, which
+ makes these standard programs treat leading-`+' operands as
+ file names and require modern usages like `-n 10' instead of
+ `-10'. Whether defined here or not, the default can be
+ overridden at run time via the _POSIX2_VERSION environment
+ variable.])
+ fi
+ AC_MSG_RESULT($gl_default_posix2_version)
+ AC_ARG_VAR(
+ [DEFAULT_POSIX2_VERSION],
+ [POSIX version to default to; see 'config.hin'.])
])