src/comp: force at least on entry in the trace-hashmap.

If there is no entry, `gperf` produce an error and the make fail.

Signed-off-by: Jean Privat <jean@pryen.org>
nitg: merge `-no-stacktrace` and `-nit-stacktrace` into a single `--stacktrace`

And make `gperf` the default (expect for nitg-g)

The C stack-trace only is unreadable for most users.

The dependence on gperf is fine since it is packaged if Debian.
The option `--stacktrace libunwind` disables it.
The option `--stacktrace none` disables the whole stacktrace.

Signed-off-by: Jean Privat <jean@pryen.org>
ballz: do not use --no-stacktrace in Makefile

The option is renamed but is useless anyway since plateform takes care of
these things nowadays.

Signed-off-by: Jean Privat <jean@pryen.org>
Merge: nitg: activate nit-stacktrace by default

The C stack-trace only is unreadable for most users.

The dependence on gperf is fine since it is packaged if Debian.
the option `--stacktrace` can be used to override the default behavior.

Pull-Request: #354
Reviewed-by: Lucas Bajolet <r4pass@hotmail.com>