Fix network communication on arm64

Fix network communication on arm64

Base messages consist of four uint32 integers.
Wrongly, integers are declared as a four-element uintptr_t array.
The 16 bytes are written directly by recv().
This works great for arm32, but on arm64 uintptr_t is 64 bit (8 bytes).

This patch reads four 32-bit integers and writes them into the uintptr_t
array.