Log Message:
ghc7: build fix (workaround) for NetBSD 9.x

NetBSD 9.x have libcurses with a newer major version than the
bootstrap kit is linked against. For now, work around this with
compat80. (This could also be dealt with by creating versioned
bootstrap kits, but that's more involved, and NetBSD 9.x is pre-
release software, so best to leave this off for now.) Thanks to
Greg Troxel for the compat80 hint.