>perl -wMstrict -le
"print qq{ver $]};
 for (@ARGV) {
   my $name = $_;
   $name =~ s{ \b Ma?c \K (\w) }{ \u$1}xmsg;
   print qq{'$_' -> '$name'};
   }
"  Mcdonald  Macdonald
ver 5.010001
'Mcdonald' -> 'Mc Donald'
'Macdonald' -> 'Mac Donald'