I get the error:

Assembler messages:
Fatal error: can't create Objects/mimalloc/alloc-aligned.o: No such file or directory

It appears pyperformance is building out of tree, and Objects/mimalloc/ doesn't exist in the build directory.
Manually creating the .../bench_tmpdir/build/Objects/mimalloc/ during the build allowed the build to complete.

Maybe add a Objects/mimalloc target to Makefile.pre.in ?