As dev-qt/qtwebengine fails to emerge on my system with default MAKEOPTS from make.conf I've tried to override them for this particular package. Unfortunately, regardless of the way I've chosen (via package.env or putting override option in a command line with emerge), overriding is ignored. As the same methods work with other packages flawlessly I suspect that this is package specific problem and has something to do with line 111 in qtwebengine-5.9.6-r1.ebuild, which looks like: export NINJAFLAGS="${NINJAFLAGS:--j$(makeopts_jobs) -l$(makeopts_loadavg "${MAKEOPTS}" 0) -v}"
*** This bug has been marked as a duplicate of bug 652200 ***
