rcg: models fail to build: `need_to_load_IOP_first` undefined!

Currently modules are failing to build with the following error:

WARNING: "need_to_load_IOP_first" [/var/cache/advligorts/rcg-4.0.0~dev2/src/fe/x1tst/x1tst.ko] undefined!

This symbol was removed from src/drv/ExtraSymbols.symvers in 8c01de98 (!40 (merged)), but seems to still be referenced heavily in the RCG:

~/src/advligorts 0$ grep -R need_to_load_IOP_first
src/fe/moduleLoadIop.c:int need_to_load_IOP_first;
src/fe/moduleLoadIop.c:EXPORT_SYMBOL( need_to_load_IOP_first );
src/fe/moduleLoad.c:int need_to_load_IOP_first;
src/fe/moduleLoad.c:EXPORT_SYMBOL(need_to_load_IOP_first);
src/fe/moduleLoad.c:extern int need_to_load_IOP_first;
src/fe/moduleLoad.c:	need_to_load_IOP_first = 0;
src/fe/moduleLoadApp.c:extern int need_to_load_IOP_first;
src/fe/moduleLoadApp.c:    need_to_load_IOP_first = 0;
src/fe/moduleLoadTS.c:int need_to_load_IOP_first;
src/fe/moduleLoadTS.c:EXPORT_SYMBOL( need_to_load_IOP_first );
src/fe/moduleLoadTS.c:extern int need_to_load_IOP_first;
src/fe/moduleLoadTS.c:    need_to_load_IOP_first = 0;
src/fe/moduleLoadVirtual.c:int need_to_load_IOP_first;
src/fe/moduleLoadVirtual.c:EXPORT_SYMBOL( need_to_load_IOP_first );