Workaround build failure on -fno-common toolchains like upstream gcc-10. Otherwise build fails as: ld: initc.o:(.bss+0x28): multiple definition of `HacksDisable'; cfg.o:(.bss+0x59e3): first defined here
Notably: - remove explicit arguments that match the defaults - convert everything to the right Nix types
Emulators form a class by themselves. So, they should be moved to applications/.