This is an auto-filed bug because sys-fs/mergerfs calls ar directly.
The issue was originally discovered on amd64, but it may be reproducible on other arches as well.
If you think that a different summary clarifies the issue better, feel free to change it.
Attached build log and emerge --info.
If you think it doesn't make sense fix these type of issues, I'd like to point out that won't be possible use a different AR implementation (like llvm-ar) by setting the AR variable. So this issue has been reproduced by setting the AR variable to x86_64-pc-linux-gnu-ar and by removing the /usr/bin/ar binary.
Created attachment 642404 [details]
build log and emerge --info
The bug has been closed via the following commit(s):
Author: Piotr Karbowski <firstname.lastname@example.org>
AuthorDate: 2020-08-08 19:59:01 +0000
Commit: Piotr Karbowski <email@example.com>
CommitDate: 2020-08-08 20:00:27 +0000
sys-fs/mergerfs: 2.30.0 bump
Version bump; Now uses environmental provided AR, CFLAGS, CXXFLAGS and LDFLAGS.
Signed-off-by: Piotr Karbowski <firstname.lastname@example.org>
sys-fs/mergerfs/Manifest | 1 +
...akefiles-fixes-ar-cflags-cxxflags-ldflags.patch | 83 ++++++++++++++++++++++
sys-fs/mergerfs/mergerfs-2.30.0.ebuild | 56 +++++++++++++++
3 files changed, 140 insertions(+)