# serial 12

# Copyright (C) 2001, 2003-2004, 2006, 2009-2023 Free Software Foundation, Inc.
# This file is free software; the Free Software Foundation
# gives unlimited permission to copy and/or distribute it,
# with or without modifications, as long as this notice is preserved.

# Written by Paul Eggert.

dnl From Paul Eggert.

# Define HOST_OPERATING_SYSTEM to a name for the host operating system.
AC_DEFUN([gl_HOST_OS],
[
  AC_REQUIRE([AC_CANONICAL_HOST])dnl
  AC_CACHE_CHECK([host operating system],
    [gl_cv_host_operating_system],

    [[case $host_os in

       # These operating system names do not use the default heuristic below.
       # They are in reverse order, so that more-specific prefixes come first.
       winnt*)          os='Windows NT';;
       vos*)            os='VOS';;
       sysv*)           os='Unix System V';;
       superux*)        os='SUPER-UX';;
       sunos*)          os='SunOS';;
       stop*)           os='STOP';;
       sco*)            os='SCO Unix';;
       riscos*)         os='RISC OS';;
       riscix*)         os='RISCiX';;
       qnx*)            os='QNX';;
       pw32*)           os='PW32';;
       ptx*)            os='ptx';;
       plan9*)          os='Plan 9';;
       osf*)            os='Tru64';;
       os2*)            os='OS/2';;
       openbsd*)        os='OpenBSD';;
       nsk*)            os='NonStop Kernel';;
       nonstopux*)      os='NonStop-UX';;
       netbsd*-gnu*)    os='GNU/NetBSD';; # NetBSD kernel+libc, GNU userland
       netbsd*)         os='NetBSD';;
       mirbsd*)         os='MirBSD';;
       midnightbsd*)    os='MidnightBSD';;
       knetbsd*-gnu)    os='GNU/kNetBSD';; # NetBSD kernel, GNU libc+userland
       kfreebsd*-gnu)   os='GNU/kFreeBSD';; # FreeBSD kernel, GNU libc+userland
       msdosdjgpp*)     os='DJGPP';;
       mpeix*)          os='MPE/iX';;
       mint*)           os='MiNT';;
       mingw*)          os='MinGW';;
       lynxos*)         os='LynxOS';;
       linux*)          os='GNU/Linux';;
       hpux*)           os='HP-UX';;
       hiux*)           os='HI-UX';;
       gnu*)            os='GNU';;
       freebsd*)        os='FreeBSD';;
       dgux*)           os='DG/UX';;
       dragonfly*)      os='DragonFly BSD';;
       bsdi*)           os='BSD/OS';;
       bsd*)            os='BSD';;
       beos*)           os='BeOS';;
       aux*)            os='A/UX';;
       atheos*)         os='AtheOS';;
       amigaos*)        os='Amiga OS';;
       aix*)            os='AIX';;

       # The default heuristic takes the initial alphabetic string
       # from $host_os, but capitalizes its first letter.
       [A-Za-z]*)
         os=`
           expr "X$host_os" : 'X\([A-Za-z]\)' | LC_ALL=C tr '[a-z]' '[A-Z]'
         ``
           expr "X$host_os" : 'X.\([A-Za-z]*\)'
         `
         ;;

       # If $host_os does not start with an alphabetic string, use it unchanged.
       *)
         os=$host_os;;
     esac
     gl_cv_host_operating_system=$os]])
  AC_DEFINE_UNQUOTED([HOST_OPERATING_SYSTEM],
    "$gl_cv_host_operating_system",
    [The host operating system.])
])