Some versions of BusyBox mkdir respond to ‘mkdir --version’ by
printing “mkdir: unrecognized option: --version” to stderr, and then
the version message we’re looking for, also to stderr. Adjust the
pattern matching in AC_PROG_MKDIR_P to account for this.
Problem reported by Valery Ushakov.
Resolves <https://savannah.gnu.org/support/?110971>.
* lib/autoconf/programs.m4 (AC_PROG_MKDIR_P): Fix detection of busybox mkdir.
AS_EXECUTABLE_P(["$as_dir$ac_prog$ac_exec_ext"]) || continue
case `"$as_dir$ac_prog$ac_exec_ext" --version 2>&1` in #(
'mkdir ('*'coreutils) '* | \
- 'BusyBox '* | \
+ *'BusyBox '* | \
'mkdir (fileutils) '4.1*)
ac_cv_path_mkdir=$as_dir$ac_prog$ac_exec_ext
break 3;;