0ca6331e

By: Tom Sydney Kerckhove <syd@cs-syd.eu>

addManifest: install built executables to $out/bin

The recent change to limit buildTarget to lib:$pname makes the install
phase only run 'Setup copy lib:$pname', which skips executables even
though postBuild rebuilt them. Downstream postInstall hooks (e.g.
opt-env-conf's installManpagesAndCompletions) that invoke
$out/bin/<exe> would then fail.

Prepend a postInstall that copies any executables found under dist/build
into $out/bin so the rest of the install pipeline behaves the same as
for non-instrumented packages.