The format of hp file didn't allow double quotes inside strings, and
under prof build, we include args in JOB, which may have double quotes.
When this happens, the error message is confusing to the user. This can
also happen under normal build if the executable name contains double
quite, which is unlikely though.
We fix this issue by introducing escaping for double quotes inside a
string by repeating it twice.
We also fix a buffer overflow bug when the lenght of the string happen
to be multiple of 5000.