Files:
------

- files from autoconf distrib: config.guess, config.sub, install-sh
- files for autoconf: configure.in, acconfig.h
- generated by autoconf: config.h.in, configure
- generated by configure: config.status, *Makefile, f77, dist, config.h

Problems/Suggestions:
---------------------

- do we need AC_PROG_LN_S ? (configure.in)
- is 'no default found for elf/aout' an error on linux? (configure.in)
- is SHELL=/bin/bash needed? (Makefile.in)
- should we move $exec_prefix/bin/f77 if it already exists? (Makefile.in)
- can we make f2c accept iand,... w/o declaration?
- Suggestion: make iand, ... into C-macros and append to f2c (how
  do we find f2c?)
- what about int.and.int - expressions?
- what about readonly, shared?
- default values for st_blksize and st_rdev? (libf77/stat2array.c)

Pitfalls:
---------

- the one I fall for _everytime_:

   '[' and ']' are the default m4 quote chars, if you use them
   in sh-commands in configure.in, change the quotes first:

   changequote(<<, >>)dnl
     grep [bar] foo
   changequote([, ])dnl

- watch out for AC_... macro calls without the closing ')'.
  autoconf will not complain but simply swallow everything up to
  the next closing paren, thus producing a garbled ./configure
