build: fix binary-link with ld.gold linker

build: fix binary-link with ld.gold linker

The ld.gold linker doesn't provide --format=default but needs --format=elf
instead. However, this doesn't work with ld.bfd. To avoid any linker
detection, we now link any binary file via partial-linking into a proper
object file itself and then link this object file in the final linking
step.
This also produces a fake libtool *.lo file so the libtool linking command
doesn't complain about PIC/non-PIC problems.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>