The oldest LTS version of Ubuntu, 16.04, has elfutils 0.165. This
version is missing some ELF and DWARF definitions used by drgn. Add
copies of elf.h from glibc 2.33 and dwarf.h and elfutils/known-dwarf.h
from elfutils 0.183 to get the latest definitions and drop the minimum
required version of elfutils further to 0.165.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
We currently bundle a version of elfutils with patches to export
additional stack tracing functionality. This has a few drawbacks:
- Most of drgn's build time is actually building elfutils.
- Distributions don't like packages that bundle verions of other
packages.
- elfutils, and thus drgn, can't be built with clang.
Now that we've replaced the elfutils DWARF unwinder with our own, we
don't need the patches, so we can drop the bundled elfutils and fix
these issues.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
drgn was originally my side project, but for awhile now it's also been
my work project. Update the copyright headers to reflect this, and add a
copyright header to various files that were missing it.
Now that we have the bundled version of elfutils, build it from libdrgn
and link to it. We can also get rid of the elfutils version checks from
the libdrgn code.
