Add: strnlen, strncat, safer string functions

src/libc/string.h

@@ -12,4 +12,8 @@ char* strtok(char* str, const char* delimiter);
 int atoi(char* str);
 void strcat(char* dest, const char* src);
 
+// Safer functions
+size_t strnlen(const char* str, size_t max_len);
+void strncat(char* dest, const char* src, size_t n);
+
 #endif