Error running '__rvm_make -j8'

rvm install 2.6.3

Installing Ruby from source to: /Users/huazai/.rvm/rubies/ruby-2.6.3, this may take a while depending on your cpu(s)...
ruby-2.6.3 - #downloading ruby-2.6.3, this may take a while depending on your connection...
ruby-2.6.3 - #extracting ruby-2.6.3 to /Users/huazai/.rvm/src/ruby-2.6.3 - please wait
ruby-2.6.3 - #configuring - please wait
ruby-2.6.3 - #post-configuration - please wait
ruby-2.6.3 - #compiling - please wait
Error running '__rvm_make -j8',
please read /Users/huazai/.rvm/log/1558966145_ruby-2.6.3/make.log

There has been an error while running make. Halting the installation.

在这里找到了答案：https://github.com/rvm/rvm/issues/4484

执行 rvm install 2.6.3 --with-openssl-dir=brew --prefix openssl` 即可安装成功