WSL (windows subsystem on linux) users will need to turn fsync off as of 11.2

Just in case this helps the next person who can't figure out why their
postgres server won't start today:

If you are running Postgres inside Microsoft WSL (at least on Ubuntu, maybe
on others too), and just picked up a software update to version 11.2, you
will need to go into your /etc/postgresql.conf file and set fsync=off.

This took me a while to fix because the error you message you get if you
don't is the generic:

terminating connection because of crash of another server process
2015-07-15 20:18:37 UTC The postmaster has commanded this server process to
roll back the current transaction and exit, because another server process
exited abnormally and possibly corrupted shared memory.

I spent a long time trying to completely uninstall and resintall, etc. to
recover from the "crash" although I don't think there ever was one and the
message appears on first use of the create database command even on a
completely clean install.

I don't know if this is possible/reasonable, but if the database code could
automatically turn fsync off on WSL it might save the next users some
trouble.