Per-Map Drop Rate Mapflag v1.0.0

Per-Map Drop Rate Mapflag (source diff)
Adds a droprate mapflag to modern rAthena (a port of Xantara’s old eAthena patch, rewritten for the current source). It multiplies the item drop chance of every monster that dies on the map. 100 is normal, 150 is +50%, 50 is half. Great for boosted hunting zones, events or weekly bonus maps.

Usage:

- Map script: prt_fild01 mapflag droprate 150
- Script command: setmapflag "prt_fild01", MF_DROPRATE, 150; and removemapflag "prt_fild01", MF_DROPRATE;
- Without a value it defaults to 100 (no change). To stop drops completely, use nodrop, nomobloot or nomvploot.

Details:

- Applies to normal drops, MVP item drops, and map drops when enable_bonus_map_drops is on.
- It is applied after the killer’s drop bonuses and before the 100% cap.
- It does not touch item-script bonus drops, stealing or zeny.
- @mapinfo shows DropRate N%.
- The client’s rates window shows the bonus in the Basic column, like bexp.
- Includes docs for doc/mapflags.txt.
- Applies with git apply on rAthena master. The touched files compile against the official code without warnings. Requires recompiling the map-server.

Run on: 6th rebalance - Meister - Part 1 (#9997) · rathena/rathena@e985006 (https://github.com/rathena/rathena/commit/e985006171d2eb320ee512a653f4c83aea3d81b6)