feat: some extensions to kernel standard c library. Other minor

improvements and formats

include/string.h

@@ -13,12 +13,20 @@ int memset(void *dst, int data, size_t amount);
 
 int strcpy(char *dst, const char *src);
 
+int strncpy(char *dst, const char *src, size_t n);
+
 size_t strlen(const char *str);
 
 const char *strchr(const char *s, char c);
 
+int memcmp(const void *s1, const void *s2, size_t n);
+
 int strcmp(const char *s1, const char *s2);
 
 int strncmp(const char *s1, const char *s2, int n);
 
+char *strcat(char *dest, const char *src);
+
+char *strncat(char *dest, const char *src, size_t n);
+
 #endif //NEW_KERNEL_STRING_H