Comment # 7 on bug 1227316 from Stanislav Brabec

I did a deep review of the header merge code, and it is affected by more bugs:
If ":" is missing on the last line, it crashes.
If ":" is missing on on one of previous lines, everything until the next ":" is
considered as tag name (including "\n", and it results invalid header with
possibly duplicated entries.
If the last line of the second file misses "\n" at the end, the tag is
completely lost and does not appear in the output file.

I am working on fixes.