Unable to reproduce, it is executable for me:

$ openssl sha1 tcltls-1.7.12.tar.gz
SHA1(tcltls-1.7.12.tar.gz)=
$ tar -tvf tcltls-1.7.12.tar.gz  | grep tcltls-1.7.12/configure
-rwxr-xr-x /users 193785 2017-05-01 09:46 tcltls-1.7.12/configure