Bruno Haible - 2020-09-01

Until someone has reproduced, investigated, and fixed the two issues, your best bet is
1. to use the HEAD of either the master branch or the clisp-2.50 branch at https://gitlab.com/gnu-clisp/clisp ,
2. use "make -f Makefile.devel build-porting64-gcc-portability". This is the least optimized variant. You can try out multiple variants through "build-porting64-gcc-portability multibuild-porting64-gcc".