Hadrian: Fix handling of build configuration
Previously we only took extraLibDirs
and friends from the package
description, ignoring any contribution from the LocalBuildInfo
. Fix
this. This also us to drop the redundant include and library paths
noted in #20566 (closed).
Relatedly, I fix Hadrian's treatment of --with-system-libffi
, fixing #20579 (closed).
Closes #20566 (closed). Closes #20579 (closed).