databases/kyotocabinet: add prototypes to kclangc.h declarations.
Some function declarations just use () as argument list. This is
valid C++, but not C, and clang-15 complains with -Wstrict-prototypes:
/usr/local/include/kclangc.h:261:13: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
double kcnan();
^ void
/usr/local/include/kclangc.h:268:13: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
double kcinf();
^ void
/usr/local/include/kclangc.h:1525:18: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes]
KCLIST* kclistnew();
^ void
Add the missing void.
PR: 268313