Limit the archive offset detection to files

It makes sense to avoid changing the offset and/or the archive size when
the user specifies a buffer rather than a file.

miniz_zip.c

@@ -807,7 +807,7 @@ static int mz_stat64(const char *path, struct __stat64 *buffer)
         }
 
         /* Update the archive start position, but only if not specified. */
-        if (pZip->m_pState->m_file_archive_start_ofs == 0)
+        if ((pZip->m_zip_type == MZ_ZIP_TYPE_FILE || pZip->m_zip_type == MZ_ZIP_TYPE_CFILE) && pZip->m_pState->m_file_archive_start_ofs == 0)
         {
             pZip->m_pState->m_file_archive_start_ofs = archive_ofs;
             pZip->m_archive_size -= archive_ofs;