sys/tools/amd64_ia32_vdso.sh: Pass explicit -m to ld for ld.bfd.

[jhb]

Summary

Unlike lld, ld.bfd does not intuit the default emulation from the
input files.

[kib]

IMO it is worth explicitly specify the emulation for amd64 64bit too.

BTW it is strange, I put OUTPUT_ARCH() into the ldscript. Might be, what is needed is OUTPUT_FORMAT() there as well, and then it is better than '-m', IMO.

[emaste]

I agree with both of @kib's points

[kib]

I put my attempt at D34157. Still I believe I tested with ld.bfd.

[jhb]

Actually, if we don't want to use -m with LD, then I'd rather use CC as the linker instead. gcc -m32 will DTRT and pass the right -m to ld. clang will pass it if needed as well.

[kib]

In D34143#772700, @jhb wrote:

Actually, if we don't want to use -m with LD, then I'd rather use CC as the linker instead. gcc -m32 will DTRT and pass the right -m to ld. clang will pass it if needed as well.

It required passing nostdlib, some magic to avoid linking crt*, and so on. This is why I went with direct ld invocation.

It is really not about passing or not -m, but putting as much setup as possible into linker script.