# for interoperability with automake-1.9.6 from autoconf-2.62.
# Remove this macro when we can assume autoconf >= 2.62 or
# autoconf >= 2.60 && automake >= 1.10.
-m4_if(m4_version_compare(m4_defn([AC_AUTOCONF_VERSION]),[2.62]),[-1],[
+# AC_AUTOCONF_VERSION was introduced in 2.62, so use that as the witness.
+m4_ifndef([AC_AUTOCONF_VERSION],[
m4_ifdef([AC_PROG_MKDIR_P], [
dnl For automake-1.9.6 && autoconf < 2.62: Ensure MKDIR_P is AC_SUBSTed.
m4_define([AC_PROG_MKDIR_P],
# so that mixed use of GNU C and GNU C++ and mixed use of Sun C and Sun C++
# works.
# This definition can be removed once autoconf >= 2.62 can be assumed.
-m4_if(m4_version_compare(m4_defn([AC_AUTOCONF_VERSION]),[2.62]),[-1],[
+# AC_AUTOCONF_VERSION was introduced in 2.62, so use that as the witness.
+m4_ifndef([AC_AUTOCONF_VERSION],[
AC_DEFUN([AC_C_RESTRICT],
[AC_CACHE_CHECK([for C/C++ restrict keyword], [ac_cv_c_restrict],
[ac_cv_c_restrict=no