Workstation 12.5.7 was GA as of June 22, 2017. We do not have the answer as to when the release is for 12.5.8. Customer can try downloading the Workstation Pro Tech Preview 2017 by logging into My VMware to see the new features. But at the moment there is no support update for Fedora 26 and GCC 7.
I had already tried the Tech Preview, but it fails to work with GCC 7.1.1 on F26.. ''A compatible version of gcc was not found''