misc/57841: netbsd-10 build fails with MKCROSSGDB=yes on gcc>=11

[campbell+netbsd%mumble.net@localhost]

>Number:         57841
>Category:       misc
>Synopsis:       netbsd-10 build fails with MKCROSSGDB=yes on gcc>=11
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    misc-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Jan 13 01:50:00 +0000 2024
>Originator:     Taylor R Campbell
>Release:        10
>Organization:
The NetGDB Foundation
>Environment:
>Description:
netbsd-10 is shipping with a development snapshot of gdb, rather than a released version, for reasons opaque to me.

A development snapshot builds itself with -Werror by default.

With MKCROSSGDB=yes, the tools build uses gdb's own build system, which sets -Werror according to that rule.

The gdb code doesn't build with -Werror on gcc>=11.  Sampling of errors:

error: storing the address of local variable 'jmp_buf' in'gdb_demangle_jmp_buf' [-Werror=dangling-pointer=]
error: definition of implicit copy constructor for 'partial_die_info' is deprecated because it has a user-declared copy assignment operator [-Werror,-Wdeprecated-copy]
>How-To-Repeat:
build.sh -V MKCROSSGDB=tools, on a system with gcc>=10, e.g. Ubuntu 22.04
>Fix:
Add to tools/gdb/Makefile:

CONFIGURE_ARGS+= --disable-werror