kern/54874: "modload exec_aout" fails due to missing dependencies

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

>Number:         54874
>Category:       kern
>Synopsis:       "modload exec_aout" fails due to missing dependencies
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Jan 18 21:05:00 +0000 2020
>Originator:     Izumi Tsutsui
>Release:        NetBSD 9.0_RC1
>Organization:
>Environment:
System: etBSD  9.0_RC1 NetBSD 9.0_RC1 (MODULAR) #2: Sun Jan 19 04:54:01 JST 2020  tsutsui@mirage:/s/netbsd-9/src/sys/arch/sun3/compile/MODULAR sun3
Architecture: m68k
Machine: sun3
>Description:
On NetBSD/sun3 9.0_RC1 (options EXEC_AOUT is disabled by default)
"modload exec_aout" fails:
---
 modload exec_aout
[ 1994.0000220] kobj_checksyms, 988: [exec_aout]: linker error: symbol `coredump_netbsd' not found
[ 1994.0200220] WARNING: module error: unable to affix module `exec_aout', error 8
modload: exec_aout: Exec format error
---

The missing coredump_netbsd() is in sys/kern/coredump_netbsd.c.

However it isn't configured unless options EXEC_AOUT (or EXEC_ECOFF etc.)
are defined, per sys/kern/files.kern:
---
file	kern/core_elf32.c		exec_elf32
file	kern/core_elf64.c		exec_elf64
file	kern/core_netbsd.c		exec_aout | exec_coff | exec_ecoff
---

sys/module/exec_aout/Makefile only pulls exec_aout.c so
coredump_netbsd() is not resolved.

>How-To-Repeat:
- build NetBSD/sun3 kernel with options MODULAR
  (or build kernel without EXEC_AOUT)
- modload exec_aout on single user

>Fix:
No idea.  Prepare proper dependencies in core_netbsd.c for module?

---
Izumi Tsutsui