ignore $PostgreSQL lines in regression tests?

Recently while adding $PostgreSQL markers to a bunch of .c and .h files 
I ran into trouble with the ecpg regression tests and had to revert the 
change for a handful of files. However, it occurred to me that we could 
have pg_regress tell diff to ignore such lines, by passing it the 
arguments "-I  '\$PostgreSQL:' ", which would tell it to ignore 
additions or deletions of lines matching that regex.

That would probably  also allow us to add such markers as comments in 
results files, which mightn't be a bad thing either.

I'm a bit unsure how portable this is, though. Linux, Windows and OSX 
should be ok, but they are the only OSs I run so I don't know about others.

Would this be a good thing to do?

cheers

andrew