1. For tools that use elftoolchain: always use elftoolchain's
elfdefinitions.h. Don't even think about looking at the host's
sys/exec_elf.h, which makes no sense and should never happen.
(ELF tools that don't use elftoolchain, like m68k-elf2coff,
continue to use nbincludes/sys/exec_elf.h. But no more nbincludes
hacks in elftoolchain.)
2. For kernel components (solaris, zfs, dtrace): always use
sys/exec_elf.h, even in Solaris components via sys/elf.h.
elfdefinitions.h is not wired up in the kernel build at all.
3. For most userland components that involve libelf: use
elfdefinitions.h via libelf header files (libelf.h, gelf.h).
libdtrace in particular requires _all_ R_* reloc type definitions,
but sys/exec_elf.h brings in only the _current machine's_ R_*
reloc type definitions. (While here: Use uintptr_t instead of
Elf_Addr for pointer-to-integer cast, since Elf_Addr is MD and
provided only by sys/exec_elf.h, not by elfdefinitions.h.)
And most userland components using libelf don't rely on any
properties of the current machine from sys/exec_elf.h, so they can
use libelf's elfdefinition.h.
Exceptions:
- dtrace drti.c relies on link.h -> link_elf.h -> sys/exec_elf.h,
but it also relies on sys/dtrace.h -> sys/elf.h ->
elfdefinitions.h like other userland components using sys/elf.h.
- kdump-ioctl.c uses sys/exec_elf.h directly and sys/dtrace.h ->
sys/elf.h -> elfdefinitions like other userland components using
sys/elf.h.
- t_ptrace_wait.c (via t_ptrace_core_wait.h) uses libelf to parse
core files, but relies on sys/exec_elf.h for struct
netbsd_elfcore_procinfo.
None of these exceptions needs all R_* reloc type definitions, so
as a workaround, we can just suppress libelf's elfdefinitions.h by
defining _SYS_ELFDEFINITIONS_H_ and use sys/exec_elf.h in these
exceptions.
And undo the whole BUILTIN_ELF_HEADERS mistake. This was:
- half bogus workarounds for missing build_install dependencies in
tools/Makefile, which are no longer missing now, and
- half futile attempt to use src/sys/sys/exec_elf.h via nbincludes in
tools involving libelf instead of libelf's elfdefinitions.h, which
collides.
Longer-term, we may wish to unify sys/exec_elf.h and libelf's
elfdefinitions.h, so we don't have to play these games.
But at least now the games are limited to three .c files (one of
which is generated by Makefile.ioctl-c), rather than haphazardly
applied tree-wide by monstrous kludges in widely used .h files with
broken hackarounds to get the tools build lurching to completion.
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