* Merged stgMalloc and execPage into a single function which handles
  even multiple pages correctly.

* Enabled the use VirtualProtect on x86 WinDoze now. This could be
  necessary for processors which distinguish between READ and EXECUTE
  memory accesses, e.g. Itaniums IIRC.

* Nuked pageMode and set page permissions always to READ/WRITE/EXECUTE,
  otherwise we could accidentally remove the WRITE permission.

Only mildly tested on x86 Linux, but it might be worth merging into
the STABLE branch when it turns out to work on x86 WinDoze and OpenBSD.
SimonM?