Running gem install mathematical on macOS 11.0 results in an error:
gem.log
mathematical.c:104:5: error: implicit declaration of function 'mtex2MML_free_string' is invalid in C99 [-Werror,-Wimplicit-function-declaration]
mtex2MML_free_string(mathml);
Running
gem install mathematical
on macOS 11.0 results in an error: gem.log