buildbot try stopped working after upgrade to master

[pepsiman]

Before upgrade, from 0.8.7, "buildbot try" with master-side mercurial steps did:

'hg' '--verbose' 'import' '--no-commit' '-p' '1' '-'

After upgrading, it now does:

'patch' '-p1' '--remove-empty-files' '--force' '--forward' '-i' '.buildbot-diff'

which fails on my Windows slaves:

'patch' is not recognized as an internal or external command, operable program or batch file.

The behaviour was changed in: ​https://github.com/buildbot/buildbot/commit/866794ae336a8fce92e005aad1e8e416961e387d#L4L258

[dustin]

pepsiman, can you have a look at

​https://github.com/buildbot/buildbot/pull/878