curl provides xz tarballs instead of lzma since v7.55.0. Consider changing to it from bz2; just changing bz2 to xz in SRC_URI should work (e.g. on next bump)
commit ba1936104bdc5d7db9e2b088984b17490b662c1f Author: Anthony G. Basile <blueness@gentoo.org> Date: Thu May 23 10:30:32 2019 -0400 net-misc/curl: version bump to 7.65.0, security bug #686050 Signed-off-by: Anthony G. Basile <blueness@gentoo.org> Package-Manager: Portage-2.3.62, Repoman-2.3.11