We just found out (thanks to Chrishas from IRC) that building larger C++ projects (llvm in this case) with -j5 (5 threads in parallel) is too much for the Pine with 2GB RAM, running out of memory... so I would recommend to set MAKEOPTS="-j3" instead of -j5 in /etc/portage/make.conf and override that if necessary for lighter builds...
Come have a chat in the Pine IRC channel >>