Proposal: Add setEnv/unsetEnv to "base"

[Simon Hengel]

Hi,
setting environment variables is possible on both POSIX and Windows
systems.  Currently this functionally is missing from
System.Environment; the "unix" package provides an implementation for
POSIX systems.

I propose to add setEnv/unsetEnv to System.Environment, so that it is
easier to write applications that behave the same on POSIX and Windows
systems.

I implemented both in a way, so that they behave exactly the same on
POSIX and Windows (modulo case sensitivity on Windows).

For now I prepared a standalone implementation [1] and corresponding
tests [2].  That implementation depends on the "unix" package.  If the
proposal is accepted, I will prepare a patch against "base" that
includes the relevant code from "unix".

Discussion Period: 2 Weeks

Cheers,
Simon

[1] https://github.com/sol/setenv/blob/master/src/System/SetEnv.hs
[2] https://github.com/sol/setenv/blob/master/test/System/SetEnvSpec.hs