The CPU cost of iterating over the relevant ELF structures is probably
negligible (despite the amount of code involved), but there is no need
to keep the containing page mapped in RAM when it doesn't have to be.
Signed-off-by: Michael Livshin <michael.livshin@scylladb.com>
get_nt_build_id() constructs a pointer by adding a base and an
offset, but if the base happens to be zero, that is undefined
under C++ rules (altough legal ELF).
Fix by performing the addition on integers, and only then
casting to a pointer.
Closes#7379
