#define _POSIX_SOURCE before #including it.
* aclocal.m4 (GUILE_STRUCT_UTIMBUF): New test.
* acconfig.h: New comment text for above CPP symbol.
* configure.in: Call it.
* posix.c: #define _POSIX_SOURCE if it seems necessary.
* configure.in: Call AC_TYPE_MODE_T.
(AC_CHECK_HEADERS): Add libc.h, to get more prototypes on the
NeXT. Put header file list in alphabetical order.
* configure, scmconfig.h.in: Regenerated.
* filesys.c [HAVE_LIBC_H]: #include <libc.h>.
* acconfig.h: New file, providing documentation for the CPP
symbols defined in configure.in
* acconfig-1.5.h: Removed; superceded by the above.