Fix Mac build for Xcode 16.3 (#1558)

Author: neebyA

src/util/helpers/StringHelpers.h

@@ -2,6 +2,92 @@
 #include "boost/nowide/convert.hpp"
 #include <charconv>
 
+// Definition for removed templates in Apple Clang 17
+#if defined(__apple_build_version__) && (__apple_build_version__ >= 17000000)
+namespace std {
+	template<>
+	struct char_traits<uint16be> {
+		using char_type = uint16be;
+		using int_type = int;
+		using off_type = streamoff;
+		using pos_type = streampos;
+		using state_type = mbstate_t;
+
+		static inline void constexpr assign(char_type& c1, const char_type& c2) noexcept {
+			c1 = c2;
+		}
+
+		static inline constexpr bool eq(char_type c1, char_type c2) noexcept {
+			return c1 == c2;
+		}
+
+		static inline constexpr bool lt(char_type c1, char_type c2) noexcept {
+			return c1 < c2;
+		}
+
+		static constexpr int compare(const char_type* s1, const char_type* s2, size_t n) {
+			for (; n; --n, ++s1, ++s2) {
+				if (lt(*s1, *s2)) return -1;
+				if (lt(*s2, *s1)) return 1;
+			}
+			return 0;
+		}
+
+		static constexpr size_t length(const char_type* s) {
+			size_t len = 0;
+			for (; !eq(*s, char_type(0)); ++s) ++len;
+			return len;
+		}
+
+		static constexpr const char_type* find(const char_type* s, size_t n, const char_type& a) {
+			for (; n; --n) {
+				if (eq(*s, a))
+					return s;
+				++s;
+			}
+			return nullptr;
+		}
+
+		static constexpr char_type* move(char_type* s1, const char_type* s2, size_t n) {
+			if (n == 0) return s1;
+			return static_cast<char_type*>(memmove(s1, s2, n * sizeof(char_type)));
+		}
+
+		static constexpr char_type* copy(char_type* s1, const char_type* s2, size_t n) {
+			if (n == 0) return s1;
+			return static_cast<char_type*>(memcpy(s1, s2, n * sizeof(char_type)));
+		}
+
+		static constexpr char_type* assign(char_type* s, size_t n, char_type a) {
+			char_type* r = s;
+			for (; n; --n, ++s)
+				assign(*s, a);
+			return r;
+		}
+
+		static inline constexpr char_type to_char_type(int_type c) noexcept {
+			return char_type(c);
+		}
+
+		static inline constexpr int_type to_int_type(char_type c) noexcept {
+			return int_type(c);
+		}
+
+		static inline constexpr bool eq_int_type(int_type c1, int_type c2) noexcept {
+			return c1 == c2;
+		}
+
+		static inline constexpr int_type eof() noexcept {
+			return static_cast<int_type>(EOF);
+		}
+
+		static inline constexpr int_type not_eof(int_type c) noexcept {
+			return eq_int_type(c, eof()) ? ~eof() : c;
+		}
+	};
+}
+#endif
+
 // todo - move the Cafe/PPC specific parts to CafeString.h eventually
 namespace StringHelpers
 {