/usr/lib/x86_64-linux-gnu/pkgconfig/ is in samba-dev 2:4.3.8+dfsg-0ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/x86_64-linux-gnu/pkgconfig/samba-hostconfig.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/samba-credentials.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/samdb.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/registry.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/gensec.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/smbclient-raw.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/ndr_krb5pac.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/dcerpc_server.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/dcerpc_samr.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/samba-util.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/ndr_standard.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/dcerpc_atsvc.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/samba-policy.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/torture.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/ndr.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/dcerpc.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/ndr_nbt.pc
/usr/lib/x86_64-linux-gnu/pkgconfig/netapi.pc