buildcfg.txt: Make M_EPISOD appear in doom2.wad
buildcfg.txt: Make M_EPISOD appear in doom2.wad

The texture appears in id's Doom II and fixes issues with ZDoom.

Signed-off-by: Mike Swanson <517655fde76fa2f07143b6c6f1774e4fae45930a@gmail.com>

jmtd/freedoom,CWolfRU/freedoom,jmtd/freedoom,jmtd/freedoom,CWolfRU/freedoom