Handle gcc48 bootstrap issues as fatal

/bin/sh: error while loading shared libraries: libgcc_s.so.1: cannot open shared object file

is a setup issue, not a host issue. Handle it as such
Handle Build time marker in build log

Ignore the build time prefix while scanning the build log, e.g.

[34698s] /bin/sh: error while loading shared libraries: libgcc_s.so.1: cannot open shared object file: No such file or directory