Gdb: use gdb from LCG release

Frank Winklmeierrequested to merge
fwinkl/atlasexternals:find_gdb into main

As discussed on !1170 (merged) there is no need to build our own gdb anymore. This MR does:

  • Cleanup of External/Gdb before retirement. The gdbhacks have been moved to atlas/athena where they are easier to update (athena!77155 (merged)). The atlasAddress2Line utility is unmaintained/obsolete. We keep the package around just in case we need to build gdb again ourselves.
  • Add a Findgdb module to setup gdb from LCG.
  • Remove the build of gdb and add find_package(gdb) to all relevant projects.
  • Fix a few bugs related to the use of the xyz_DIR and xyz_DIRS variables that went unnoticed so far.

cc @ssnyder

This MR requires !1176 (merged).

Edited by Frank Winklmeier

Merge request reports