Paul Eggert wrote:
> I would think that a patch would be welcome for Autoconf,
> just as it is for gnulib -- we like to support GNU systems
> well.
Thanks for the advice. Now that the patch has been accepted in Autoconf,
it's more straightforward to override AC_FUNC_CHOWN in Autoconf < 2.70.
I'm applying this:
2012-05-03 Bruno Haible <br...@clisp.org>
chown: Avoid "guessing no" when cross-compiling to glibc systems.
* m4/chown.m4 (AC_FUNC_CHOWN): Override in autoconf < 2.70.
--- m4/chown.m4.orig Fri May 4 04:10:18 2012
+++ m4/chown.m4 Fri May 4 04:10:12 2012
@@ -1,4 +1,4 @@
-# serial 26
+# serial 27
# Determine whether we need the chown wrapper.
dnl Copyright (C) 1997-2001, 2003-2005, 2007, 2009-2012 Free Software
@@ -14,6 +14,56 @@
# From Jim Meyering.
+m4_version_prereq([2.70], [] ,[
+
+# This is taken from the following Autoconf patch:
+#
http://git.savannah.gnu.org/gitweb/?p=autoconf.git;a=commitdiff;h=7fbb553727ed7e0e689a17594b58559ecf3ea6e9
+AC_DEFUN([AC_FUNC_CHOWN],
+[
+ AC_REQUIRE([AC_TYPE_UID_T])dnl
+ AC_REQUIRE([AC_CANONICAL_HOST])dnl for cross-compiles
+ AC_CHECK_HEADERS([unistd.h])
+ AC_CACHE_CHECK([for working chown],
+ [ac_cv_func_chown_works],
+ [AC_RUN_IFELSE(
+ [AC_LANG_PROGRAM(
+ [AC_INCLUDES_DEFAULT
+ [#include <fcntl.h>
+ ]],
+ [[
+ char *f = "conftest.chown";
+ struct stat before, after;
+
+ if (creat (f, 0600) < 0)
+ return 1;
+ if (stat (f, &before) < 0)
+ return 1;
+ if (chown (f, (uid_t) -1, (gid_t) -1) == -1)
+ return 1;
+ if (stat (f, &after) < 0)
+ return 1;
+ return ! (before.st_uid == after.st_uid && before.st_gid ==
after.st_gid);
+ ]])
+ ],
+ [ac_cv_func_chown_works=yes],
+ [ac_cv_func_chown_works=no],
+ [case "$host_os" in # ((
+ # Guess yes on glibc systems.
+ *-gnu*) ac_cv_func_chown_works=yes ;;
+ # If we don't know, assume the worst.
+ *) ac_cv_func_chown_works=no ;;
+ esac
+ ])
+ rm -f conftest.chown
+ ])
+ if test $ac_cv_func_chown_works = yes; then
+ AC_DEFINE([HAVE_CHOWN], [1],
+ [Define to 1 if your system has a working `chown' function.])
+ fi
+])# AC_FUNC_CHOWN
+
+])
+
AC_DEFUN_ONCE([gl_FUNC_CHOWN],
[
AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
