c99 changed meaning of inline keyword. This exposed linker failures on gcc-6 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 fixes linkage by explicitly marking functions as 'static inline'.