(svn r24417) -Codechange: [Win32] Don't needlessly include windows.h in a commonly used header.

src/os/windows/win32.cpp

@@ -89,6 +89,19 @@ void OSOpenBrowser(const char *url)
  * modified from Jan Wassenberg's GPL implementation posted over at
  * http://www.gamedev.net/community/forums/topic.asp?topic_id=364584&whichpage=1&#2398903 */
 
+struct DIR {
+	HANDLE hFind;
+	/* the dirent returned by readdir.
+	 * note: having only one global instance is not possible because
+	 * multiple independent opendir/readdir sequences must be supported. */
+	dirent ent;
+	WIN32_FIND_DATA fd;
+	/* since opendir calls FindFirstFile, we need a means of telling the
+	 * first call to readdir that we already have a file.
+	 * that's the case iff this is true */
+	bool at_first_entry;
+};
+
 /* suballocator - satisfies most requests with a reusable static instance.
  * this avoids hundreds of alloc/free which would fragment the heap.
  * To guarantee concurrency, we fall back to malloc if the instance is