This is an auto-filed bug because dev-ruby/metasm does not respect CFLAGS/LDFLAGS. 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. NOTE: To reproduce this issue you may want to set CFLAGS="${CFLAGS} -frecord-gcc-switches" and LDFLAGS="${LDFLAGS} -Wl,--defsym=__gentoo_check_ldflags__=0". If this is not something about c/c++ context you may want to set also FFLAGS and FCFLAGS or just see this bug as an hint to hide the QA warning where is not possible to respect CFLAGS/LDFLAGS.
Created attachment 640308 [details] build.log build log and emerge --info
tinderbox_musl has reproduced this issue with version 1.0.5-r1 - Updating summary.