lang/gcc>=11: Warn about LTO_BOOTSTRAP

[salvadore]

Summary

Warn users about the amount of ram and time needed to build GCC with
LTO_BOOTSTRP enabled.

PR: 264949
Reported by: Tomoaki AOKI <[e-mail]> and others

[gerald]

Thank you for thinking of our users impacted negatively, Lorenzo.

I think this is the minimum we can do and only suggest tweaking the message a little (breaking the long sentence and one or two style changes) and, for now, only applying this to the "production" ports, that is, skipping the -devel ports (though the latter is more an intuition which you are welcome to ignore).

lang/gcc12/pkg-help

4

How about a minor variation along the lines of:

Building this port with LTO_BOOTSTRAP enabled requires significant amounts of memory and time. Consider disabling LTO_BOOTSTRAP in favor of STANDARD_BOOTSTRAP (or disabling BOOTSTRAP altogether) in case that is a problem.

[salvadore]

Thanks Gerald, I have committed the message in the form you suggested. I have committed it both in production and development ports: while I trust your intuition, I really do not see how an additional warning could be problematic, it seems to me that it has only advantages. On the other hand, more differences we have in our gcc ports, more complexity we add to their maintainance.