[Nix-dev] re2c fix build

[Vladimír Čunát]

On 07/09/2017 03:34 AM, Karn Kallio via nix-dev wrote:
> The attached patch fixes the build of the re2c Nixpkgs expression by
> adjusting the sourceRoot to account for the unpackFile treatment of a
> directory.

Note: I had to "undo" that anyway in 3a891c67fc87, as the change was
caused by commits that I didn't manage to fixup before they reached master.

--Vladimir