C bug/feature

[utzoo!henry]

The C compiler rejects most control characters in source code with
"Unknown character" error messages, but does not do so for control-A
(ASCII SOH).  Furthermore, SOH suppresses the incrementing of cc's
line-number counter for the first newline following, so it messes up
line numbering for following error messages.

This is actually vestigial code, rather than an error of omission.
In the days before #line, the preprocessor had to have some way to
suppress line-number incrementing in the text of a #include file,
so it stuck an SOH on the front of each line, and the compiler paid
special attention to this.

Is there anything out there that still uses this cryptic feature?
If not, it should die, as a possible source of user confusion.