Admittedly only tried www-client/firefox-60.5.2 but if you try to build it against dev-libs/libevent[-threads], you get an undefined reference for EVENT__SIZEOF_PTHREAD_T. Probably not noticed because threads is enabled by default. Perhaps this is needed in mozconfig-v6.52.eclass too.
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=5456cc63ca98978657246de6dd595efe7889736a commit 5456cc63ca98978657246de6dd595efe7889736a Author: Thomas Deutschmann <whissi@gentoo.org> AuthorDate: 2019-03-17 22:17:44 +0000 Commit: Thomas Deutschmann <whissi@gentoo.org> CommitDate: 2019-03-17 22:19:53 +0000 www-client/firefox: USE=system-libevent requires dev-libs/libevent[threads] Closes: https://bugs.gentoo.org/680638 Package-Manager: Portage-2.3.62, Repoman-2.3.12 Signed-off-by: Thomas Deutschmann <whissi@gentoo.org> eclass/mozconfig-v6.60.eclass | 2 +- www-client/firefox/firefox-65.0.2.ebuild | 2 +- www-client/firefox/firefox-66.0_rc3.ebuild | 2 +- 3 files changed, 3 insertions(+), 3 deletions(-) Additionally, it has been referenced in the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=41bbf1b0752fe6f4a9edbf37f4e4ac738f95b2b4 commit 41bbf1b0752fe6f4a9edbf37f4e4ac738f95b2b4 Author: Thomas Deutschmann <whissi@gentoo.org> AuthorDate: 2019-03-17 22:19:38 +0000 Commit: Thomas Deutschmann <whissi@gentoo.org> CommitDate: 2019-03-17 22:19:54 +0000 mail-client/thunderbird: USE=system-libevent requires dev-libs/libevent[threads] Bug: https://bugs.gentoo.org/680638 Package-Manager: Portage-2.3.62, Repoman-2.3.12 Signed-off-by: Thomas Deutschmann <whissi@gentoo.org> mail-client/thunderbird/thunderbird-60.5.3.ebuild | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
The bug has been referenced in the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=d2290335b595a9474200ebd8d0db97e5dbe029cd commit d2290335b595a9474200ebd8d0db97e5dbe029cd Author: Thomas Deutschmann <whissi@gentoo.org> AuthorDate: 2019-03-17 22:21:20 +0000 Commit: Thomas Deutschmann <whissi@gentoo.org> CommitDate: 2019-03-17 22:21:20 +0000 eclass/mozconfig-v6.52: USE=system-libevent requires dev-libs/libevent[threads] Bug: https://bugs.gentoo.org/680638 Signed-off-by: Thomas Deutschmann <whissi@gentoo.org> eclass/mozconfig-v6.52.eclass | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
