The gtk-doc and pkgconfig dependencies don't need to be cross-compiled, so they should be in BDEPEND. I'll attach a patch to the latest ebuild, but maybe it could be done when adding a new version (bug #710788).
Created attachment 679518 [details, diff] fix.patch
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=64ce94937cc7e8d4e13af758e6c7462bc170f73b commit 64ce94937cc7e8d4e13af758e6c7462bc170f73b Author: Craig Andrews <candrews@gentoo.org> AuthorDate: 2021-01-07 17:29:22 +0000 Commit: Matt Turner <mattst88@gentoo.org> CommitDate: 2021-01-08 02:33:44 +0000 net-libs/libmbim: 1.24.4 version bump Closes: https://bugs.gentoo.org/710788 Closes: https://bugs.gentoo.org/761733 Closes: https://github.com/gentoo/gentoo/pull/18985 Signed-off-by: Craig Andrews <candrews@gentoo.org> Signed-off-by: Matt Turner <mattst88@gentoo.org> net-libs/libmbim/Manifest | 1 + net-libs/libmbim/libmbim-1.24.4.ebuild | 37 ++++++++++++++++++++++++++++++++++ 2 files changed, 38 insertions(+)