Re: new compile command doesn't coalesce errors on the same line

[Richard Stallman]

    Unquoted string "foo" may clash with future reserved word at -e line 1.
    Name "main::y" used only once: possible typo at -e line 1.
    Name "main::x" used only once: possible typo at -e line 1.
    Use of uninitialized value in concatenation (.) or string at -e line 1.

It is not unusual to have unrelated errors on the same line.
That happens in C as well.

However, once next-error shows the user the line, he will see
all the error messages about it, and will probably fix them all.
If the next use of next-error goes to the second error on that line,
the user just finds it a nuisance.  He has to type next-error
several times just to get to an error he hasn't deal with already.

So we want next-error to go to the next error for a different place.