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      1 # double-slash-root.m4 serial 4   -*- Autoconf -*-
      2 dnl Copyright (C) 2006, 2008, 2009 Free Software Foundation, Inc.
      3 dnl This file is free software; the Free Software Foundation
      4 dnl gives unlimited permission to copy and/or distribute it,
      5 dnl with or without modifications, as long as this notice is preserved.
      6 
      7 AC_DEFUN([gl_DOUBLE_SLASH_ROOT],
      8 [
      9   AC_REQUIRE([AC_CANONICAL_HOST])
     10   AC_CACHE_CHECK([whether // is distinct from /], [gl_cv_double_slash_root],
     11     [ if test x"$cross_compiling" = xyes ; then
     12 	# When cross-compiling, there is no way to tell whether // is special
     13 	# short of a list of hosts.  However, the only known hosts to date
     14 	# that have a distinct // are Apollo DomainOS (too old to port to),
     15 	# Cygwin, and z/OS.  If anyone knows of another system for which // has
     16 	# special semantics and is distinct from /, please report it to
     17 	# <bug-gnulib (a] gnu.org>.
     18 	case $host in
     19 	  *-cygwin | i370-ibm-openedition)
     20 	    gl_cv_double_slash_root=yes ;;
     21 	  *)
     22 	    # Be optimistic and assume that / and // are the same when we
     23 	    # don't know.
     24 	    gl_cv_double_slash_root='unknown, assuming no' ;;
     25 	esac
     26       else
     27 	set x `ls -di / // 2>/dev/null`
     28 	if test "$[2]" = "$[4]" && wc //dev/null >/dev/null 2>&1; then
     29 	  gl_cv_double_slash_root=no
     30 	else
     31 	  gl_cv_double_slash_root=yes
     32 	fi
     33       fi])
     34   if test "$gl_cv_double_slash_root" = yes; then
     35     AC_DEFINE([DOUBLE_SLASH_IS_DISTINCT_ROOT], [1],
     36       [Define to 1 if // is a file system root distinct from /.])
     37   fi
     38 ])
     39