MFH: r561432

games/sauerbraten: fix build on GCC architectures

In file included from engine/rendermodel.cpp:28:
engine/md2.h: In constructor 'md2::md2(const char*)':
engine/md2.h:74: error: class 'md2' does not have any field named 'vertloader'
engine/md2.h:74: error: no matching function for call to 'vertloader<md2>::vertloader()'
engine/vertmodel.h:433: note: candidates are: vertloader<MDL>::vertloader(const char*) [with MDL = md2]
engine/vertmodel.h:432: note: vertloader<md2>::vertloader(const vertloader<md2>&)