Add a new GDB_LIBEXEC option to install gdb and kgdb to /usr/libexec.

[jhb]

Summary

Add a new GDB_LIBEXEC option to install gdb and kgdb to /usr/libexec.

When this option is enabled, only gdb and kgdb are installed to /usr/libexec
for use by crashinfo(8). Other bits of GDB such as gdbserver and gdbtui
are not installed. For this option to be effective, GDB must be enabled.

Rework r317094 to re-enable GDB on all platforms but enable GDB_LIBEXEC
on platforms for which the GDB in ports is a superset of functionality.

This is a compromise suggested by kib@.

Test Plan

• have not yet tested this, will follow up once I have

[emaste]

tools/build/mk/OptionalObsoleteFiles.inc

2441 ↗

(On Diff #27618)

} placement

[emaste]

usr.sbin/crashinfo/crashinfo.sh

43 ↗

(On Diff #27618)

maybe /usr/libexec/gdb before /usr/bin/gdb? I can imagine not-really-supported upgrade paths that have both, where /usr/bin/gdb is an old leftover.

60 ↗

(On Diff #27618)

quotes unnecessary

158 ↗

(On Diff #27618)

Perhaps emit a suggestion to install the kgdb package or port?

[kib]

I am fine with /usr/libexec/{,k}gdb, and I agree with the changes in whole. I cannot provide useful comments on the details of the make infrastructure changes, except what Ed noted.

[jhb]

• Review feedback.

[emaste]

LGTM with one nit as noted

tools/build/mk/OptionalObsoleteFiles.inc

2441 ↗

(On Diff #27674)

} still in wrong spot?

[jhb]

• Include src.opts.mk.

[emaste]

tools/build/mk/OptionalObsoleteFiles.inc

2441 ↗

(On Diff #27687)

This is still ${MK_GDB_LIBEXEC == yes} not ${MK_GDB_LIBEXEC} == yes

[jhb]

• Add another include of src.opts.mk.
• Correct } location.

[jhb]

tools/build/mk/OptionalObsoleteFiles.inc

2446 ↗

(On Diff #27690)

Will commit this separately.

2451 ↗

(On Diff #27690)

I need to delete these if MK_GDB == no as well.

usr.sbin/crashinfo/crashinfo.sh

158 ↗

(On Diff #27618)

I'm a bit hesitant to do that here. For one, this script can be run during boot. Secondly, some platforms don't have a working kgdb yet. (RISC-V just doesn't have a kernel debugger at all). Given that we will ship /usr/libexec/kgdb until klldb exists I think that this message will only really be seen on systems like RISC-V.

[emaste]

LGTM modulo the minor updates you mentioned

gnu/usr.bin/gdb/Makefile.inc

3 ↗

(On Diff #27690)

I'm not sure where Makefile.inc gets included from (if that place may already include src.opts.mk?), but LGTM if this is needed.

[jhb]

• Delete /usr/libexec/*gdb if WITHOUT_GDB=yes is set.

[jhb]

Finally passed various tests on my laptop by doing installworld with WITHOUT_GDB=yes, WITHOUT_GDB_LIBEXEC=yes, and default (WITH_GDB_LIBEXEC=yes) and verifying the correct things get installed, and that 'make check-old' with either WITHOUT_GDB=yes, or WITHOUT_GDB_LIBEXEC=yes or the default all report the right things for each of the 3 installed world cases.

gnu/usr.bin/gdb/Makefile.inc

3 ↗

(On Diff #27690)

The various child Makefiles (gdb/Makefile, gdbtui/Makefile, etc.) do not currently include src.opts.mk as they don't need it.