This is an auto-filed bug because sys-apps/syscriptor 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 642266 [details]
build log and emerge --info
The bug has been closed via the following commit(s):
Author: Sam James <firstname.lastname@example.org>
AuthorDate: 2021-08-13 20:04:55 +0000
Commit: Sam James <email@example.com>
CommitDate: 2021-08-13 21:28:34 +0000
sys-apps/syscriptor: update EAPI 6 -> 7, respect CC
Signed-off-by: Sam James <firstname.lastname@example.org>
...iptor-1.5.15-dont-inject-additional-flags.patch | 30 ++++++++++++++++++++++
...or-1.5.15-respect-CC-environment-variable.patch | 25 ++++++++++++++++++
sys-apps/syscriptor/syscriptor-1.5.15.ebuild | 22 ++++++++++++----
3 files changed, 72 insertions(+), 5 deletions(-)