Regression: Ctrl-c from the pager in an alias exits it

I'm experiencing an issue when using aliases for commands that open the pager. When I press Ctrl-c from the pager, it exits. This does not happen when I don't use an alias and did not happen before. It causes problems because Ctrl-c is also used for other things, such as canceling a search that hasn't completed.

To reproduce, create e.g. the alias `l = log` and run `git l`. Then press Ctrl-c. The expected behavior is that nothing happens. The actual behavior is that the pager exits.

I bisected the repo, and found that the commit 86d26f240 [0] introduced the issue.

[0]: 86d26f240 (setup.c: re-fix d95138e (setup: set env $GIT_WORK_TREE
                when .. - 2015-12-20)