Simpler: just add this line:
compiler.blacklist clang
Instead of a complete new Portfile, you should provide a unified diff of your changes so that they are easier to review. I'll attach this.
When you report that a port will not build, you should attach the main.log file so that we can see how it failed. I'll attach this too. The error it shows is:
:info:build Undefined symbols for architecture x86_64:
:info:build "_buildcommand", referenced from:
:info:build _openinfo in pinfo-filehandling_functions.o
:info:build "_builddircommand", referenced from:
:info:build _opendirfile in pinfo-filehandling_functions.o
:info:build ld: symbol(s) not found for architecture x86_64
