math: make sure PTRDIFF_MAX and INT_MAX are defined before using them.

src/lol/math/arraynd.h

@@ -26,12 +26,13 @@
 #include <lol/base/array.h>
 #include <lol/base/assert.h>
 
+#include <cstddef>
+#include <climits>
 #include <type_traits>
 
 namespace lol
 {
 
-
 template<typename T, ptrdiff_t L>
 class arraynd_initializer
 {
@@ -275,5 +276,9 @@ private:
 template<typename... T> using array2d = arraynd<2, T...>;
 template<typename... T> using array3d = arraynd<3, T...>;
 
+/* Make sure these macros exist since we use them in preprocessor tests. */
+static_assert(PTRDIFF_MAX > 0, "missing PTRDIFF_MAX");
+static_assert(INT_MAX > 0,     "missing INT_MAX");
+
 } /* namespace lol */