Add native Windows binary for bison.

bison/src/bison/2.4.1/bison-2.4.1-src/m4/dos.m4

+#serial 10   -*- autoconf -*-
+
+# Define some macros required for proper operation of code in lib/*.c
+# on MSDOS/Windows systems.
+
+# Copyright (C) 2000, 2001, 2004, 2005, 2006 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.
+
+# From Jim Meyering.
+
+AC_DEFUN([gl_AC_DOS],
+  [
+    AC_CACHE_CHECK([whether system is Windows or MSDOS], [ac_cv_win_or_dos],
+      [
+        AC_TRY_COMPILE([],
+        [#if !defined _WIN32 && !defined __WIN32__ && !defined __MSDOS__ && !defined __CYGWIN__
+neither MSDOS nor Windows
+#endif],
+        [ac_cv_win_or_dos=yes],
+        [ac_cv_win_or_dos=no])
+      ])
+
+    if test x"$ac_cv_win_or_dos" = xyes; then
+      ac_fs_accepts_drive_letter_prefix=1
+      ac_fs_backslash_is_file_name_separator=1
+      AC_CACHE_CHECK([whether drive letter can start relative path],
+                     [ac_cv_drive_letter_can_be_relative],
+        [
+          AC_TRY_COMPILE([],
+          [#if defined __CYGWIN__
+drive letters are always absolute
+#endif],
+          [ac_cv_drive_letter_can_be_relative=yes],
+          [ac_cv_drive_letter_can_be_relative=no])
+        ])
+      if test x"$ac_cv_drive_letter_can_be_relative" = xyes; then
+        ac_fs_drive_letter_can_be_relative=1
+      else
+        ac_fs_drive_letter_can_be_relative=0
+      fi
+    else
+      ac_fs_accepts_drive_letter_prefix=0
+      ac_fs_backslash_is_file_name_separator=0
+      ac_fs_drive_letter_can_be_relative=0
+    fi
+
+    AC_DEFINE_UNQUOTED([FILE_SYSTEM_ACCEPTS_DRIVE_LETTER_PREFIX],
+      $ac_fs_accepts_drive_letter_prefix,
+      [Define on systems for which file names may have a so-called
+       `drive letter' prefix, define this to compute the length of that
+       prefix, including the colon.])
+
+    AH_VERBATIM(ISSLASH,
+    [#if FILE_SYSTEM_BACKSLASH_IS_FILE_NAME_SEPARATOR
+# define ISSLASH(C) ((C) == '/' || (C) == '\\')
+#else
+# define ISSLASH(C) ((C) == '/')
+#endif])
+
+    AC_DEFINE_UNQUOTED([FILE_SYSTEM_BACKSLASH_IS_FILE_NAME_SEPARATOR],
+      $ac_fs_backslash_is_file_name_separator,
+      [Define if the backslash character may also serve as a file name
+       component separator.])
+
+    AC_DEFINE_UNQUOTED([FILE_SYSTEM_DRIVE_PREFIX_CAN_BE_RELATIVE],
+      $ac_fs_drive_letter_can_be_relative,
+      [Define if a drive letter prefix denotes a relative path if it is
+       not followed by a file name component separator.])
+  ])