- Correct gnulib dependency to PATCH_DEPENDS, per Bapt.
- Rely on USE_AUTOTOOLS :env to pull in automake for BUILD.
- Move re-automake rule to pre-configure, when the tool is available.
- Adapt installed gelf.h header to define needed non-standard Elf types as
needed, rather than trying to add them to base elf headers.
Reviewed by: portlint
Sponsored by: EMC / Isilon Storage Division