update elf.h from Debian Trixie musl-dev 1.2.5-3.1~deb13u1

[illwieckz]

Update elf.h from Debian Trixie musl-dev 1.2.5-3.1~deb13u1.

The breakpad merge of upstream requires newer ELF symbols. By updating this Musl elf.h file beforehand, we don't have to implement compat code at merge time, and it doesn't delay the fix for after the merge. On merge commit, all platforms that was working before the merge will find the updated elf.h file and miss no symbols.

Actually it's possible to use that Musl elf.h file on every platform, and delete all the compatibility code, but upstream added more compatibility code instead of updating that file, so the NUKING of the compatibility code will happen after the merge.

[illwieckz]

Actually, two more commits related to ELF things can be merged beforehand. We can avoid relying on system elf.h and link.h on all platforms, it makes the code very straightforward as it removes all conditionals.

I included them in the branch.

[slipher]

LGTM