[dev] [slstatus] "make dist" is broken

[Steve Ward]

I noticed these problems with the dist target.
    components/*.c aren't copied to slstatus-0/components/
    slstatus.h isn't copied to slstatus-0/

Another minor thing I noticed in config.def.h is that some of the
descriptions have "____ in GB", but fmt_human makes the unit prefix
dynamic.