* acspecific.m4 (AC_FUNC_CHOWN): New macro, based on Jim

* acspecific.m4 (AC_FUNC_CHOWN): New macro, based on Jim
Meyering's `chown.m4' serial 4.
(AC_FUNC_GETGROUPS): New macro, based on Jim Meyering's
`getgroups.m4' serial 3.
(AC_FUNC_MEMCMP): Updated, based on Jim Meyering's `memcmp.m4'
serial 3.
(AC_FUNC_MALLOC): New macro, based on Jim Meyering's
`malloc.m4' serial 3.
(AC_FUNC_MMAP): Include `stdlib.h' when `STDC_HEADERS'.
* acfunctions: Sort.
Add `chown' and `malloc', point `getgroups' to `AC_FUNC_GETGROUPS'
instead of `AC_TYPE_GETGROUPS'.
* doc/autoconf.texi (Particular Functions): Adjust.