git-svn-id: https://crawl-ref.svn.sourceforge.net/svnroot/crawl-ref/trunk@3672 c06c8d41-db1a-0410-9941-cceddc491573
KNJLUJP4LYWMVVSXUBYVEXTUNPC2HJRTTSO77ITTHMEA5CKDT7MQC
4OV4JZ6NWQ2ZK4LEWCUWALLB3BVANJJ2EMLHC5LJLA5WYSP25OIQC
JDZCDMUCQ7VENYVLB62KQWUIRGABID37OKATOKCBUPCDL7W75NPAC
K2CS6TCX2NDVL2ASEHGP4J4K4IJ6FP3ANNKTSIWVG43HPYSBX6ZQC
if (posx < 0 || posx >= GXM || posy < 0 || posy >= GYM) return -1;
if (posx < 0 || posx >= GXM || posy < 0 || posy >= GYM)
return -1;