Cygwin: implement fdclosedir

fdclosedir is BSD-only but already present in dirent.h for a couple
of years.

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>

winsup/cygwin/cygwin.din

@@ -520,6 +520,7 @@ fcvt SIGFE
 fcvtbuf SIGFE
 fcvtf SIGFE
 fdatasync SIGFE
+fdclosedir SIGFE
 fdim NOSIGFE
 fdimf NOSIGFE
 fdiml NOSIGFE

winsup/cygwin/dir.cc

@@ -267,9 +267,8 @@ rewinddir (DIR *dir)
   __endtry
 }
 
-/* closedir: POSIX 5.1.2.1 */
-extern "C" int
-closedir (DIR *dir)
+static int
+closedir_worker (DIR *dir, int *fdret)
 {
   __try
     {
@@ -280,21 +279,44 @@ closedir (DIR *dir)
 
 	  int res = ((fhandler_base *) dir->__fh)->closedir (dir);
 
-	  close (dir->__d_fd);
+	  if (fdret)
+	    *fdret = dir->__d_fd;
+	  else
+	    close (dir->__d_fd);
+
 	  free (dir->__d_dirname);
 	  free (dir->__d_dirent);
 	  free (dir);
-	  syscall_printf ("%R = closedir(%p)", res, dir);
 	  return res;
 	}
       set_errno (EBADF);
     }
   __except (EFAULT) {}
   __endtry
-  syscall_printf ("%R = closedir(%p)", -1, dir);
   return -1;
 }
 
+/* closedir: POSIX 5.1.2.1 */
+extern "C" int
+closedir (DIR *dir)
+{
+  int res;
+
+  res = closedir_worker (dir, NULL);
+  syscall_printf ("%R = closedir(%p)", res, dir);
+  return res;
+}
+
+extern "C" int
+fdclosedir (DIR *dir)
+{
+  int fd = -1;
+
+  closedir_worker (dir, &fd);
+  syscall_printf ("%d = fdclosedir(%p)", fd, dir);
+  return fd;
+}
+
 /* mkdir: POSIX 5.4.1.1 */
 extern "C" int
 mkdir (const char *dir, mode_t mode)

winsup/cygwin/include/cygwin/version.h

@@ -487,12 +487,13 @@ details. */
   350: Add close_range.
   351: Add getlocalename_l.
   352: Implement dirent.d_reclen.
+  353: Implement fdclosedir.
 
   Note that we forgot to bump the api for ualarm, strtoll, strtoull,
   sigaltstack, sethostname. */
 
 #define CYGWIN_VERSION_API_MAJOR 0
-#define CYGWIN_VERSION_API_MINOR 352
+#define CYGWIN_VERSION_API_MINOR 353
 
 /* There is also a compatibity version number associated with the shared memory
    regions.  It is incremented when incompatible changes are made to the shared

winsup/cygwin/release/3.6.0

@@ -3,6 +3,8 @@ What's new:
 
 - New API call: getlocalename_l.
 
+- New API call: fdclosedir.
+
 
 What changed:
 -------------