This is an auto-filed bug because media-sound/mp3asm calls cc 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 CC implementation (like clang) by setting the CC variable. So this issue has been reproduced by setting the CC variable to x86_64-pc-linux-gnu-gcc and by removing the /usr/bin/cc - /usr/bin/gcc binaries.
Created attachment 641046 [details]
build log and emerge --info
The bug has been closed via the following commit(s):
Author: David Seifert <email@example.com>
AuthorDate: 2020-06-21 13:19:55 +0000
Commit: David Seifert <firstname.lastname@example.org>
CommitDate: 2020-06-21 13:19:55 +0000
media-sound/mp3asm: [QA] Run autoreconf
Package-Manager: Portage-2.3.101, Repoman-2.3.22
Signed-off-by: David Seifert <email@example.com>
.../mp3asm/files/mp3asm-0.1.3-fix-autotools.patch | 11 +++++++++++
media-sound/mp3asm/mp3asm-0.1.3-r2.ebuild | 18 +++++++++++-------
2 files changed, 22 insertions(+), 7 deletions(-)