devel/9base: fix build on powerpc64
Fix kcmp() collision with unistd.h:
sort.c:111:5: error: conflicting types for 'kcmp'
111 | int kcmp(Key*, Key*);
| ^/usr/include/unistd.h:525:6: note: previous declaration is here
525 | int kcmp(pid_t pid1, pid_t pid2, int type, uintptr_t idx1, uintptr_t idx2);
| ^sort.c:205:28: error: too few arguments to function call, expected 5, have 2
205 | n = kcmp(ol->key, l->key);
| ~~~~ ^