Opaque error during stack setup

[aplainzetakind]

On a gentoo system where ncurses was built without the tinfo USE flag, GHC installation failed due to the absence of libtinfo.so.6. This was only apparent after running stack setup with --verbosity=debug, and the error normally reported by stack was quite non-specific:

$ stack setup
Preparing to install GHC (ncurses6) to an isolated location.
This will not interfere with any system-level installation.
Preparing to download ghc-ncurses6-8.4.3 ...
Already downloaded.
Unpacking GHC into /home/user/.stack/programs/x86_64-linux/ghc-ncurses6-8.4.3.temp/ ...
Configuring GHC ...
Installing GHC ...
Received ExitFailure 2 when running
Raw command: /usr/bin/gmake install
Run from: /home/user/.stack/programs/x86_64-linux/ghc-ncurses6-8.4.3.temp/ghc-8.4.3/

Recompiling ncurses with the tinfo USE flag resolved the issue. Clearer error reporting in this case would be useful.

[dbaynard]

Thanks, @aplainzetakind, that's a good point. Would you be willing to make a PR?