elf.h outdated

[darealshinji]

That file's 5 years old. I would recommend you to either just delete it, since most unices should have a copy of it anyway, or you download a current copy from GNU libc:
https://www.gnu.org/software/libc/

[edolstra]

Is it a problem that it's 5 years old? (I.e. is it lacking some new definition?)

[darealshinji]

See for yourself:
https://gist.github.com/darealshinji/f7b49217ea7edb5faa92#file-diff-to-2-17-diff
https://gist.github.com/darealshinji/f7b49217ea7edb5faa92#file-diff-to-git-diff
Seems like many new definitions have been added meanwhile. And I wouldn't supply header files that are available through any modern distro.
You can let the configure script check for availability of elf.h:
https://github.com/darealshinji/patchelfmod/blob/patchelf/configure.ac

[darealshinji]

From the Fedora RPM spec:

package ships elf.h - delete to use glibc-headers one

rm src/elf.h

[darealshinji]

elf.h was updated a while ago.