drm: Fix drm.h uapi header for Windows

[James Park]

Attempting to submit patch in response to https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6162#note_712454

This will allow Mesa to port code to Windows more easily.

Hide BSD header and drm_handle_t behind _WIN32 check.

Change __volatile__ to volatile, which is standard.

James Park (1):
  drm: Fix drm.h uapi header for Windows

 include/uapi/drm/drm.h | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

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2.7.4