squash! fscache: teach fscache to use NtQueryDirectoryFile

The NtQueryDirectoryFile() call works best (and on Windows 8.1 and
earlier, it works *only*) with buffer sizes up to 64kB. Which is 32k
wide characters, so let's use that as our buffer size.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

compat/win32/fscache.c

@@ -24,7 +24,13 @@ struct fscache {
  unsigned int opendir_requests;
  unsigned int fscache_requests;
  unsigned int fscache_misses;
- WCHAR buffer[64 * 1024];
+ /*
+ * 32k wide characters translates to 64kB, which is the maximum that
+ * Windows 8.1 and earlier can handle. On network drives, not only
+ * the client's Windows version matters, but also the server's,
+ * therefore we need to keep this to 64kB.
+ */
+ WCHAR buffer[32 * 1024];
 };
 static struct trace_key trace_fscache = TRACE_KEY_INIT(FSCACHE);