X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=m4%2Fdup.m4;h=ec04d69053b98ce516408cd575a3016eea851ea4;hb=92249085071a973e2c0621b0415b93d2e48bb00d;hp=5105b6e431a9060983bf92ee6dd446cf5fa6913c;hpb=d57728a6ca2413a7c564d8b7bb13d9e5a5a180f3;p=debian%2Fgzip

diff --git a/m4/dup.m4 b/m4/dup.m4
index 5105b6e..ec04d69 100644
--- a/m4/dup.m4
+++ b/m4/dup.m4
@@ -1,5 +1,5 @@
-# dup.m4 serial 3
-dnl Copyright (C) 2011-2013 Free Software Foundation, Inc.
+# dup.m4 serial 6
+dnl Copyright (C) 2011-2018 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -7,10 +7,13 @@ dnl with or without modifications, as long as this notice is preserved.
 AC_DEFUN([gl_FUNC_DUP],
 [
   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
-  AC_REQUIRE([gl_MSVC_INVAL])
-  if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then
-    REPLACE_DUP=1
-  fi
+  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
+  m4_ifdef([gl_MSVC_INVAL], [
+    AC_REQUIRE([gl_MSVC_INVAL])
+    if test $HAVE_MSVC_INVALID_PARAMETER_HANDLER = 1; then
+      REPLACE_DUP=1
+    fi
+  ])
   dnl Replace dup() for supporting the gnulib-defined fchdir() function,
   dnl to keep fchdir's bookkeeping up-to-date.
   m4_ifdef([gl_FUNC_FCHDIR], [
@@ -19,6 +22,31 @@ AC_DEFUN([gl_FUNC_DUP],
       REPLACE_DUP=1
     fi
   ])
+  AC_CACHE_CHECK([whether dup works], [gl_cv_func_dup_works],
+    [AC_RUN_IFELSE(
+      [AC_LANG_PROGRAM([[#include <unistd.h>
+                         #include <fcntl.h>
+                         #include <errno.h>]],
+         [[/* On OS/2 kLIBC, dup does not work on a directory fd.  */
+           int fd = open (".", O_RDONLY);
+           return fd < 0 ? 1 : dup (fd) < 0 ? 2 : 0;
+         ]])
+      ],
+      [gl_cv_func_dup_works=yes],
+      [gl_cv_func_dup_works=no],
+      [case "$host_os" in
+                 # Guess no on native Windows.
+         mingw*) gl_cv_func_dup_works="guessing no" ;;
+         *)      gl_cv_func_dup_works="guessing yes" ;;
+       esac
+      ])
+    ])
+  case "$gl_cv_func_dup_works" in
+    *yes) ;;
+    *)
+      REPLACE_DUP=1
+      ;;
+  esac
 ])
 
 # Prerequisites of lib/dup.c.