Without the change archimedes fails to build with latest toolchains as:
ld: archimedes.c:(.text+0xdac7): undefined reference to `rnd'
ld: archimedes.c:(.text+0xdeab): undefined reference to `rnd'
ld: archimedes.c:(.text+0xdf13): undefined reference to `rnd'
ld: archimedes.c:(.text+0xe3ef): undefined reference to `rnd'
ld: archimedes.o:archimedes.c:(.text+0xe456): more undefined references to `rnd' follow
ld: archimedes.o: in function `EMC':
archimedes.c:(.text+0xf11b): undefined reference to `creation'
ld: archimedes.c:(.text+0xf5f5): undefined reference to `creation'
ld: archimedes.c:(.text+0xf826): undefined reference to `creation'
ld: archimedes.c:(.text+0xf9ce): undefined reference to `creation'
The change happens to fix build against clang as well.