On linux profiles openmp is enabled by default, and bullet ebuild requires threads to be enabled when openmp is, so it probably should be changed to +threads.
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=291af15b301069748e61770752ecc91b49be89cb commit 291af15b301069748e61770752ecc91b49be89cb Author: Ross Charles Campbell <rossbridger.cc@gmail.com> AuthorDate: 2021-05-10 23:36:26 +0000 Commit: Joonas Niilola <juippis@gentoo.org> CommitDate: 2021-06-02 12:59:04 +0000 sci-physics/bullet: bump to 3.17 This version reintroduced "extras" USE flag Closes: https://bugs.gentoo.org/765556 Closes: https://bugs.gentoo.org/762982 Package-Manager: Portage-3.0.18, Repoman-3.0.3 Closes: https://github.com/gentoo/gentoo/pull/20764 Signed-off-by: Joonas Niilola <juippis@gentoo.org> sci-physics/bullet/Manifest | 1 + sci-physics/bullet/bullet-3.17.ebuild | 87 +++++++++++++++++++++++++++++++++++ sci-physics/bullet/metadata.xml | 5 +- 3 files changed, 91 insertions(+), 2 deletions(-)