Grunt concat task wildcard expression doesn't work properly

Hey guys,

I'm using the concat task in one of my projects using the wildcard syntax to specify a pattern of files to match. It works fine for me.

However it seems like there are problems with the wildcard syntax on different machines. Regarding [this issue](https://github.com/PascalPrecht/wbb/issues/12), it turned out that using wildcard syntax in concat task doesn't work properly.

We fixed this temporary by specifying the files names in an array.

Is this a known issue?

Start with the Grunt concat task and reproduce the reported wildcard behavior, comparing it with the explicit file-array workaround. Review the linked wbb issue for the differing-machine context. Done means the wildcard expression behaves consistently and the failure is covered by a regression test.

Written by the indexing model from the issue text.