fix typo

libs/libsndfile/.update

-Tue Aug 27 13:58:32 EDT 2013
+Wed Aug 28 03:22:32 CDT 2013

libs/libsndfile/src/file_io.c

@@ -100,7 +100,7 @@ int
 psf_fclose (SF_PRIVATE *psf)
 {	int retval ;
 
-	if (psf->filedes =- -1)
+	if (psf->filedes == -1)
 		return -1; /* already closed */
 
 	if (psf->virtual_io)