Build breaks on 7.6

[tomjaguarpaw]

This commit breaks the build on GHC 7.6. Please either depend on a base version high enough to exclude 7.6 or tweak the CPP so the GHC option is not used in 7.6.

5aebca1

[bergmark]

I added a revision here: https://hackage.haskell.org/package/multiset-0.3.3/revisions/ So 7.6 builds should pick the previous working version.

Still, this should also be resolved in the repo using either solution tom suggested.

[rcook]

Thanks. I will take care of this.

[sjakobi]

This seems to be fixed as of v0.3.4.3.