Gentoo's Bugzilla –
Attachment 559702 Details for
Bug 674434sci-mathematics/octave-4.4.1 configure: error: ld: warning: libgfortran.so.4, needed by /usr/lib/gcc/x86_64-pc-linux-gnu/8.2.0/../../../../lib64/libblas.so, not found (try using -rpath or -rpath-link)