Start: double-bounded string mutation functions.

These bound `dest` and `src`, so will assure no OOB writes *and* no OOB reads.

Functions prototyped only, (not yet implemented.)

Fortune for naka's current commit: Middle blessing − 中吉

src/display.c

@@ -21,6 +21,18 @@ static usize strncpy_n(char*pOUT dest, const char* restrict src, usize n)
 	return i;
 }
 
+// Will not write past `dn` bytes of `dest`, will not read past `sn` bytes of `src`. Otherwise, same as `strncpy_n()`.
+static usize s_strncpy_n(usize sn, usize dn; char dest[static pOUT dn], usize dn, const char src[static restrict sn], usize sn)
+{
+	TODO("double-bounded strncpy");
+}
+
+// Will not write past `dn` bytes of `dest`, will not read past `sn` bytes of `src`. Otherwise, same as `strncat_n()`.
+static usize s_strncat_n(usize sn, usize dn; char dest[static pOUT dn], usize dn, const char src[static restrict sn], usize sn)
+{
+	TODO("double-bounded strncat");
+}
+
 // Returns number of bytes written to (dest+strlen(dest)). Otherwise same as `strncat()`.
 static inline usize strncat_n(char*pOUT dest, const char* restrict src, usize n)
 {