You can use the configure option --with-module-suffix=.so (as Arch, Fedora and Debian are doing) to bypass the usage of .la files Thanks :)
Supposedly since 1.24 we wouldn't even need to pass that option: (from its NEWS file) - Using plain dlopen()/LoadLibrary() for opening modules instead of libltdl. This also means that --with-module-suffix is gone in configure.
The bug has been closed via the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=4be3e189525739c0e323e63494014801a637adeb commit 4be3e189525739c0e323e63494014801a637adeb Author: Andreas Sturmlechner <asturm@gentoo.org> AuthorDate: 2018-08-22 22:39:36 +0000 Commit: Andreas Sturmlechner <asturm@gentoo.org> CommitDate: 2018-08-22 22:41:37 +0000 media-sound/mpg123: Remove .la files Closes: https://bugs.gentoo.org/593736 Package-Manager: Portage-2.3.48, Repoman-2.3.10 media-sound/mpg123/mpg123-1.25.10-r1.ebuild | 105 ++++++++++++++++++++++++++++ 1 file changed, 105 insertions(+)