[Bug libstdc++/81797] gcc 7.1.0 fails to build on macOS 10.13 (High Sierra):

[dam at cosinux dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81797

--- Comment #79 from Damien Merenne <dam at cosinux dot org> ---
not -j1. Only the LN_S trick.