This largely copies over Spicy's `.clang-format` configuration file. The
one place where we deviate is header include order since Zeek depends on
headers being included in a certain order.
realpath() apparently doesn't handle Windows symlinks very well. This
causes plugin::Manager and ScannedFile to rescan a bunch of extra
paths that they should be skipping. This commit reduces the startup
time on Windows by 3-4 seconds (~8.5s to ~5s).
#1835 subtly changed the semantics of the `LoadFile` plugin hook to no
longer have the current script location available for signature files
being loaded through `@load-sigs`. This was undocumented behavior, so
it's technically not a regression, but since at least one external
plugin is depending on it, this change restores the old behavior.
This (1) fixes an issue where signature files supplied on the command
line wouldn't pass through the hooks, and (2) prepares for allowing
hooks to supply the content of a signature file directly.
