Use intptr_t to hold the buffer pointer for in-process imaging.
Use intptr_t to hold the buffer pointer for in-process imaging.

Required to fix the 64-bit MSYS2/MinGW64 build with
in-process-imaging turned on.

godbyk/OSVR-Core,feilen/OSVR-Core,feilen/OSVR-Core,feilen/OSVR-Core,godbyk/OSVR-Core,OSVR/OSVR-Core,godbyk/OSVR-Core,leemichaelRazer/OSVR-Core,feilen/OSVR-Core,feilen/OSVR-Core,leemichaelRazer/OSVR-Core,OSVR/OSVR-Core,godbyk/OSVR-Core,leemichaelRazer/OSVR-Core,leemichaelRazer/OSVR-Core,leemichaelRazer/OSVR-Core,OSVR/OSVR-Core,OSVR/OSVR-Core,godbyk/OSVR-Core,godbyk/OSVR-Core,OSVR/OSVR-Core,OSVR/OSVR-Core