Cygwin: fix declaration of RtlInitEmptyUnicodeString

This avoids "-Werror=maybe-uninitialized" errors due to
using WCSTR accidentally.

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

winsup/cygwin/ntdll.h

@@ -1638,13 +1638,14 @@ extern "C"
 
   /* RtlInitEmptyUnicodeString is defined as a macro in wdm.h, but that file
      is missing entirely in w32api. */
+
   inline
-  VOID NTAPI RtlInitEmptyUnicodeString(PUNICODE_STRING dest, PCWSTR buf,
+  VOID NTAPI RtlInitEmptyUnicodeString(PUNICODE_STRING dest, PWSTR buf,
 				       USHORT len)
   {
     dest->Length = 0;
     dest->MaximumLength = len;
-    dest->Buffer = (PWSTR) buf;
+    dest->Buffer = buf;
   }
   /* Like RtlInitEmptyUnicodeString, but initialize Length to len, too.
      This is for instance useful when creating a UNICODE_STRING from an

winsup/cygwin/syscalls.cc

@@ -561,7 +561,7 @@ try_to_bin (path_conv &pc, HANDLE &fh, ACCESS_MASK access, ULONG flags)
     {
       /* In the remote case we need the full path, but recycler is only
 	 a relative path.  Convert to absolute path. */
-      RtlInitEmptyUnicodeString (&fname, (PCWSTR) tp.w_get (),
+      RtlInitEmptyUnicodeString (&fname, tp.w_get (),
 				 (NT_MAX_PATH - 1) * sizeof (WCHAR));
       RtlCopyUnicodeString (&fname, pc.get_nt_native_path ());
       RtlSplitUnicodePath (&fname, &fname, NULL);