• Add a way to specify a different compiler to be used in the
  "Makefile" by calling Makefile.PL with the CC environment variable
  set to the path to the alternate compiler.
  
  • This way we can use CC=/usr/bin/clang perl Makefile.PL
    in order to compile faster.
    
• LibXML.pm (_clone): Fix typo in line_numbers handling.
  
  • Thanks to Bernhard Reutner-Fischer for the report and fix.