Fix windows 64-bit builds

pid_t is 64-bit in 64-bit mingw, but the windows process/thread
functions return a DWORD(uint32_t). Instead of promoting to a pid_t and
fixing the format strings, just use a uint32_t to store the values.

android_thread_id also cannot be a 64-bit pointer, so for windows just
force it to be a uint32_t.

libutils/ProcessCallStack only works under Linux, since it makes heavy
use of /proc. Don't compile it under Windows or Darwin.

Bug: 26957718
Change-Id: I4e43e7cf18a96f22b3a9a08dbab8c3e960c12930