Pharaoh - Pharaoh-hophra (Jer 37:7; Jer 44:30), the successor of Necho (2Ki 23:29).
Neither ... make for him - literally, “effect (anything) with him,” that is, be of any avail to Zedekiah. Pharaoh did not act in concert with him, for he was himself compelled to retire to Egypt.
by casting up mounts, etc. - So far from Pharaoh doing so for Jerusalem, this was what Nebuchadnezzar did against it (Jer 52:4). Calvin Maurer, etc., refer it to Nebuchadnezzar, “when Nebuchadnezzar shall cast up mounts.”