Fix issues with int to string conversion in ox string operations

deps/ox/src/ox/std/string.hpp

@@ -35,6 +35,8 @@ class BString {
 
 		const BString &operator+=(char *str);
 
+		const BString &operator+=(int64_t i);
+
 		bool operator==(const BString &other);
 
 		char *data();
@@ -106,7 +108,14 @@ const BString<size> &BString<size>::operator+=(const char *str) {
 
 template<size_t size>
 const BString<size> &BString<size>::operator+=(char *str) {
-	return *this = (const char*) str;
+	return *this += (const char*) str;
+}
+
+template<size_t size>
+const BString<size> &BString<size>::operator+=(int64_t i) {
+	char str[65];
+	ox_itoa(i, str);
+	return this->operator+=(str);
 }
 
 template<size_t buffLen>

deps/ox/src/ox/std/strops.cpp

@@ -81,6 +81,7 @@ int ox_atoi(const char *str) {
 }
 
 char *ox_itoa(int64_t v, char *str) {
+	if (v) {
 		auto mod = 1000000000000000000;
 		constexpr auto base = 10;
 		auto it = 0;
@@ -104,5 +105,11 @@ char *ox_itoa(int64_t v, char *str) {
 				it++;
 			}
 		}
+		str[it] = 0;
+	} else {
+		// 0 is a special case
+		str[0] = '0';
+		str[1] = 0;
+	}
 	return str;
 }