Add native numpy handling when plotting vectors of (unsigned) long long

matplotlibcpp.h

@@ -296,6 +296,14 @@ template <> struct select_npy_type<uint16_t> { const static NPY_TYPES type = NPY
 template <> struct select_npy_type<uint32_t> { const static NPY_TYPES type = NPY_ULONG; };
 template <> struct select_npy_type<uint64_t> { const static NPY_TYPES type = NPY_UINT64; };
 
+// Sanity checks; comment them out or change the numpy type below if you're compiling on
+// a platform where they don't apply
+static_assert(sizeof(long long) == 8);
+template <> struct select_npy_type<long long> { const static NPY_TYPES type = NPY_INT64; };
+static_assert(sizeof(unsigned long long) == 8);
+template <> struct select_npy_type<unsigned long long> { const static NPY_TYPES type = NPY_UINT64; };
+// TODO: add int, long, etc.
+
 template<typename Numeric>
 PyObject* get_array(const std::vector<Numeric>& v)
 {