Compiling on MacOS, simple change enables compilation.

[tonyvsuk]

Hello,

If it helps, the following change gets "tdigest.c" to compile on MacOS.

#if !defined(APPLE)
#define LONG_LONG_MAX LLONG_MAX // may need some other term for Mac/linux
#define DBL_MAX DBL_MAX
#endif //#if !defined(APPLE)

All the best,

Tony.