unistd-safer: Implement pipe_safer on native Windows.

* lib/pipe-safer.c (pipe_safer): Don't test HAVE_PIPE.
* modules/unistd-safer (Depends-on): Add pipe-posix.

ChangeLog

@@ -1,3 +1,9 @@
+2020-12-24  Bruno Haible  <bruno@clisp.org>
+
+	unistd-safer: Implement pipe_safer on native Windows.
+	* lib/pipe-safer.c (pipe_safer): Don't test HAVE_PIPE.
+	* modules/unistd-safer (Depends-on): Add pipe-posix.
+
 2020-12-24  Bruno Haible  <bruno@clisp.org>
 
 	execute: Use posix_spawn by default on native Windows.

lib/pipe-safer.c

@@ -30,7 +30,6 @@
 int
 pipe_safer (int fd[2])
 {
-#if HAVE_PIPE
   if (pipe (fd) == 0)
     {
       int i;
@@ -39,18 +38,15 @@ pipe_safer (int fd[2])
           fd[i] = fd_safer (fd[i]);
           if (fd[i] < 0)
             {
-              int e = errno;
+              int saved_errno = errno;
               close (fd[1 - i]);
-              errno = e;
+              errno = saved_errno;
               return -1;
             }
         }
 
       return 0;
     }
-#else
-  errno = ENOSYS;
-#endif
 
   return -1;
 }

modules/unistd-safer

@@ -12,6 +12,7 @@ m4/unistd-safer.m4
 Depends-on:
 fcntl
 unistd
+pipe-posix
 
 configure.ac:
 gl_UNISTD_SAFER