Log parser misses an error

[nathangrigg]

The parse_log script, which is taken from the rubber project, fails to catch an error if it is listed on a line that immediately follows a line of length 79 characters.

For example, if the log looks like this

This line of the log that contains exactly 79 characters, confusing the script.
! Undefined control sequence.
l.33 A deformation of an $R$-linear \category
                                        $\C$ to $S$

then the parser assumes that the error line is a continuation of the first.