RFE: sync line format

[Malte Starostik]

Hello,

I'm using m4 1.4 on both GNU/Linux and Windows XP to preprocess SQL
scripts.
The first lines of the input are:

changecom(--)dnl
changequote({,})dnl

Now, I would like to use sync lines, but then the output script will
cause SQL syntax errors because the sync lines still start with #.  I'd
like to propose that future m4 versions use user-defined comment
delimiters when generating sync lines.

Thanks alot in advance,
-Malte