Found in the Debian port:
http://deb.debian.org/debian/pool/main/t/tcltls/tcltls_1.7.22-2.debian.tar.xz

Index: tlsBIO.c
--- tlsBIO.c.orig
+++ tlsBIO.c
@@ -231,9 +231,12 @@ static long BioCtrl(BIO *bio, int cmd, long num, void 
 	switch (cmd) {
 		case BIO_CTRL_RESET:
 			dprintf("Got BIO_CTRL_RESET");
-			num = 0;
+			ret = 0;
+			break;
 		case BIO_C_FILE_SEEK:
 			dprintf("Got BIO_C_FILE_SEEK");
+			ret = 0;
+			break;
 		case BIO_C_FILE_TELL:
 			dprintf("Got BIO_C_FILE_TELL");
 			ret = 0;