Simple Attack Micro AI: code cleanup
Swarm Micro AI: code cleanup
Lurkers Micro AI: code cleanup
Patrol Micro AI: code cleanup
Guardian Micro AIs: code cleanup
Tweaks to two event triggers

Allows units other than Gweddry to find the gold, and triggers the
academy-finding dialogue when moving close to it, but not if Dacyn
already got there first.
Don't bother with stolen gold if there wasn't any
scons: link statically against libstdc++ and libgcc for mingw32 cross-compile
Properly memset a variable.

Issue found by cppcheck.
disallow undo when action was sended

we now disallow undoing actions that we already sended over the network.
We also disallow undoing moves when the rng was invoked like it's done
for recruits/recalls already.
revmoved unused code

this typedef was a leftover from my original plan to pass functions to
run_in_synced_context. I decided to pass strings to
run_in_synced_context at some time.
remove outdated comments.