Warning in geqo_main.c from clang 13

Hi,

Clang 13 on my machine and peripatus (but not Apple clang 13 on eg
sifika, I'm still confused about Apple's versioning but I think that's
really llvm 12-based) warns:

geqo_main.c:86:8: warning: variable 'edge_failures' set but not used
[-Wunused-but-set-variable]
        int                     edge_failures = 0;

Here's one way to silence it.