update paths in analyse-dumps.sh

also mask out childno to make hashing work better.
move sigwas extern to header
add -D__linux__ just for sparse use.
use NULL instead of 0 for gettimeofday 2nd param
use NULL as pointer in shmget, not 0
make a bunch of sparse missing prototype warnings go away

really every syscalls/*.c should be including this, but as they all include
sanitise.h, we can just put it here once.
fix sparse warnings in sync_file_range about long constants.
remove unnecessary include
make a bunch of things static