autoconf auxdir

[Lars J. Aas]

1) I've become quite a fan of using the AC_CONFIG_AUX_DIR macro, and I
   wouldn't mind if one was set up in Autoconf too.  Are there good reasons
   for not setting one up?

2) We ought to unify the way these macros are named:

   AC_CONFIG_AUX_DIR
   AC_CONFIG_SRCDIR

   One ought to change and be AU_DEFUN'ed, and sooner rather than later
   IMO (before 2.50).  Any opinions on this?  Any other such convention-
   breaking names in the package?

  Lars J