while you should be overriding -j# on `emake` lines, if you do want to tweak it via MAKEOPTS, you should be appending, not clobbering the variable broken code: sci-physics/mpb/mpb-1.4.2-r1.ebuild:47: MAKEOPTS="-j1" emake || die # Parallel 'make' gives syntax errors. sci-physics/mpb/mpb-1.4.2-r1.ebuild:52: MAKEOPTS="-j1" emake || die sci-physics/mpb/mpb-1.4.2-r1.ebuild:57: MAKEOPTS="-j1" emake || die sci-physics/mpb/mpb-1.4.2-r1.ebuild:63: MAKEOPTS="-j1" emake || die
was fixed in sci-physics/mpb-1.4.2-r2, r1 now removed.