This is an auto-filled bug because media-libs/libnsgif calls cc directly. The issue was originally discovered on amd64, but it may be reproducible on other arches as well. Attached build log and emerge --info. NOTE: To reproduce this issue you may want to temporarily move the /usr/bin/cc - /usr/bin/gcc binaries.
Created attachment 633832 [details] build.log build log and emerge --info
This was fixed in August 2020 when we reworked the netsurf eclass.