Stop crashing on RELR sections.

[woutershep]

I just added the new constants to the file and it works for my use case.
I have no idea if this is enough or even correct though...

Please see https://maskray.me/blog/2021-10-31-relative-relocations-and-relr

[heirecka]

Seems to work for my purposes as well. But maybe section.rb should be teached about RELR too:

diff --git a/lib/elf/section.rb b/lib/elf/section.rb
index 41c8fc7..283a2a9 100644
--- a/lib/elf/section.rb
+++ b/lib/elf/section.rb
@@ -270,6 +270,7 @@ module Elf
              16 => [ :PreinitArray, 'Array of pre-constructors' ],
              17 => [ :Group, 'Section group' ],
              18 => [ :SymTabShndx, 'Extended section indeces' ],
+             19 => [ :Relr, 'RELR relative relocations' ],
              # OS-specific range start
              0x6ffffff8 => [ :Checksum, 'Checksum for DSO content' ]
              # OS-specific range end