dtrace: Add WITH_DTRACE_ASAN.

[domagoj.stolfa_gmail.com]

Summary

This option is a blanket for all the DTrace-related software. The option
enables passes in -fsanitize=address -fsanitize=undefined, enabling ASAN
and UBSAN in the following components:

• libdtrace
• dtrace(1)
• lockstat(1)
• plockstat(1)

The option defaults to "no" and is intended as a developer aid.

Test Plan

Apply this patch, echo 'WITH_DTRACE_ASAN=' >> /etc/src.conf and rebuild.

[markj]

This is missing an option description, i.e., tools/build/options/WITH_DTRACE_ASAN needs to be added.

[domagoj.stolfa_gmail.com]

Add tools/build/options/WITH_DTRACE_ASAN and update src.conf.

If there's any other preference for the text that should be contained in the man pages, I would be happy to replace it.

[markj]

tools/build/options/WITH_DTRACE_ASAN

3

[emaste]

tools/build/options/WITH_DTRACE_ASAN

2

$FreeBSD$ is no longer needed, you can leave it out

[domagoj.stolfa_gmail.com]

Address the comments by markj and emaste.

[domagoj.stolfa_gmail.com]

Remove a leftover .\".

[domagoj.stolfa_gmail.com]

Add a missing newline to the option file and regenerate src.conf.5.

[markj]

Could you please mail me a git diff to apply to main?