make install broken (no libcore.so)

[HeroesGrave]

cannot access x86_64-unknown-linux-gnu/stage2/lib/libcore-*.so: No such file or directory

IIRC, libcore was .rlib only, so I guess this is just a makefile problem.

[HeroesGrave]

Look like a duplicate of #14026, except it's (I presume) failing on all systems.

[alexcrichton]

Closing as a dupe of #14026