Enable PKCS#7 signature parsing for modinfo.

Packages describing “pkcs7” as local USE flag

Package “pkcs7” Flag Description
sys-apps/kmod Enable PKCS#7 signature parsing for modinfo.
dev-libs/libjcat Enable PKCS7 verification support via net-libs/gnutls
sys-apps/fwupd Enable PKCS7 verification support via net-libs/gnutls

All packages providing a “pkcs7” USE flag (2)