Although using some of the following macros was required in past releases, you should not use any of them in new code. All these macros will be removed in the next major Automake version; if you are still using them, running autoupdate should adjust your configure.ac automatically (see Using autoupdate to Modernize configure.ac). Do it NOW!
mkdir_pto one of
install-sh -d, or
Nowadays Autoconf provides a similar functionality with
AC_PROG_MKDIR_P (see Particular Program Checks), however this defines
the output variable
MKDIR_P instead. In case you are still
AM_PROG_MKDIR_P macro in your configure.ac,
or its provided variable
$(mkdir_p) in your Makefile.am,
you are advised to switch ASAP to the more modern Autoconf-provided
interface instead; both the macro and the variable will be
removed in the next major Automake release.