Another try to fix libsodium.

zpostfacto · zpostfacto · commit c1df31b4f2fe · 2020-02-06T10:59:26.000-08:00
Maaaaaybe I should actually get setup to build it for realz, so I am not
submitting fixes blind?

Nah.
diff --git a/src/common/crypto_25519_libsodium.cpp b/src/common/crypto_25519_libsodium.cpp
@@ -1,4 +1,7 @@
 #include "crypto.h"
+#include "crypto_25519.h"
+
+#include <tier0/dbg.h>
 
 #ifdef STEAMNETWORKINGSOCKETS_CRYPTO_25519_LIBSODIUM
 
