pkgconf-2.9.91
bomtool: use SOURCE_DATE_EPOCH for default creation time if set
spdxtool: use SOURCE_DATE_EPOCH for default creation time if set
cli: rework unveil processing to allow it to be bypassed
cli: add --link-abi query implementation
SPDX-License-Identifier: Add files with BSD-2-Clause, BSD-4-Clause and SUDO license
cli: update copyright in --about
SPDX-License-Identifier: Add files with pkgconf license