10.5 Leopard circular dependency on gcc7 gcc8 gcc9

[Chris Jones]

> 
> Artax:~ multix$ gcc-mp-7
> gcc-mp-7: fatal error: no input files
> compilation terminated.
> Artax:~ multix$ gcc-mp-6
> gcc-mp-6: fatal error: no input files
> compilation terminated.

those errors are to be expected as you didn't give gcc anything to 
compile ...