not installed as "autoconf", pass it explicitly (along with the
accompanying "autom4te") when calling `bootstrap' and `configure'.
For example:
- $ AUTOCONF=autoconf2.67 AUTOM4TE=autom4te2.67 ./bootstrap
- $ ./configure AUTOCONF=autoconf2.67 AUTOM4TE=autom4te2.67
+ $ AUTOCONF=autoconf2.68 AUTOM4TE=autom4te2.68 ./bootstrap
+ $ ./configure AUTOCONF=autoconf2.68 AUTOM4TE=autom4te2.68
* Dependent files aclocal.m4, configure and Makefile.in in all
directories should be up to date in the git repository, so that