bug fix for recursive token expansion

[tvandijck]

added test in gmake2.

[starkos]

Would it be possible to get a test that shows the recursive expansion? The gmake tests on this PR don't seem to show it?

[tvandijck]

Actually the test was a proof of failure, the title of the PR may be a little off.. but it was a bug in the "recurse" function that is inside of the detoken function.
https://github.com/premake/premake-core/pull/927/files#diff-99f714b3251ec87d2c34c37944ca560cR172

At first iteration the 'field' could be nil, while in consecutive iterations it would become the right value. I have no idea if that is a lua bug, or whatever it is, but passing field down as an argument fixed it. The caching added in that function is just a performance improvement.

So the result of the test before the fix would be that the first item in the postbuildcommands was expanded correctly, while the second item would be treated like an absolute path, and chop of everything before the token expansion.

[starkos]

Ah, got it. Carry on then.