(Potential buffer over-read) Ensure the string g_player[i].wchoice is properly formatted.

Same as issue terminx/eduke32#293 (closed). Reproduced in certain builds of NetDuke32 as a crash when a weapon becomes out of ammo, possibly with great chances while using the "weapons stay" option.

I don't know the exact cause of having wchoice set as described here - could be a random cfg corruption of a known kind - but I had wchoice set to the string "secwd22221" for NetDuke32. It can be changed from the relevant cfg file and console altogether.

Within P_CheckWeapon, this leaded to a buffer over-read.