Add missing cast.

code/Common/ZipArchiveIOSystem.cpp

@@ -126,7 +126,7 @@ voidpf IOSystem2Unzip::opendisk(voidpf opaque, voidpf stream, uint32_t number_di
 
     char *disk_filename = (char*)malloc(io_stream->m_Filename.length() + 1);
     strncpy(disk_filename, io_stream->m_Filename.c_str(), io_stream->m_Filename.length() + 1);
-    for (i = io_stream->m_Filename.length() - 1; i >= 0; i -= 1)
+    for (i = (int)io_stream->m_Filename.length() - 1; i >= 0; i -= 1)
     {
         if (disk_filename[i] != '.')
             continue;