AC_FUNC_* and cross-compiling

[Dan Kegel]

It looks like a lot of AC_FUNC_* macros are not
cross-compile-friendly, as they use AC_RUN_IFELSE.

Is an appropriate way to deal with these to
set environment variables before running config,
to tell it what it can't figure out itself?
e.g.
  ac_cv_func_mmap_fixed_mapped=yes ./configure
?  That seems to do it for betaftpd.
- Dan

p.s. here are some of the macros in question:

AC_FUNC_CHOWN
AC_FUNC_CLOSEDIR_VOID
AC_FUNC_FNMATCH
AC_FUNC_GETGROUPS
AC_FUNC_GETPGRP
AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK
AC_FUNC_MALLOC
AC_FUNC_MEMCMP
AC_FUNC_MKTIME
AC_FUNC_MMAP
AC_FUNC_SETPGRP
AC_FUNC_STRTOD
AC_FUNC_STRERROR_R
AC_FUNC_STRCOLL
AC_FUNC_UTIME_NULL
AC_FUNC_FORK
AC_FUNC_WAIT3