[boost] [concept_check] Merge changes to master

Subject: [boost] [concept_check] Merge changes to master
From: Daniel James (daniel_at_[hidden])
Date: 2013-12-08 07:11:00

Hi,

I merged some old changes to master, all warning fixes, all old enough
to be fully tested on trunk:

https://github.com/boostorg/concept_check/commit/229e3055a03210da4dd10d43bc5d26cd89267593
https://github.com/boostorg/concept_check/commit/ccd9f52467953f4b569f52cb6a61ba6d41de09ee
https://github.com/boostorg/concept_check/commit/9521991561bf574772ce48d38c299c488f3ef62d
https://github.com/boostorg/concept_check/commit/168e60aa3d5238cd25b341661a6c53e638dd6c33

I cherry picked the first two because they're a bit old. It's a bit
late now, but do you think I should have done this as a pull request?

Daniel