Use alternative program for macro editor (Tools=>Options=>Advanced)
You can substitute the GSAK macro editor with any program of your choosing. The parameters section also support 3 special tags that will allow you to pass information to that program:
%file - The macro file being run
%line - The line number in the macro if invoked from a macro error
%col - The column number in the line if invoked from a macro error
You would normally combine these special tags with the command line switches that your text editor supports.
The path to your macro editor also support the special tag %programfiles. This comes in handy when you restore your settings on different computers that have a different %programfiles path (For example, going from a 32 bit edition of Windows to a 64 bit edition)
Note: There is a quirk when using " (double quotes) to enclose the whole field. Instead use chr(34) if you want to use double quotes. For more information see this link