4GB virtual memory is too small and causes things to fault.
Previously we were at `1 << 36` but it caused oom issues on devices with
smaller amounts of memory.
This time ensure the the SHM memory is allocated with MEM_NORESERVE so
devices can actually allocate the virtual memory region.
We need to reserve that space for EXEC apps and 32bit apps. Hard throw a
warning if any of our mapping space ends up in the lower 32bits.
PIE and potentially a custom dynamic linker can enforce this.
Stefanos Kornilios Mitsis Poiitidis