gallium: do not wrap header inclusion in

gallium: do not wrap header inclusion in

Add one missing extern C guard within include/pipe/p_video_enums.h, and
remove the wrapping throughout gallium.

On Haiku one could even use the gallium debug_printf() although
that's another topic.

v2: Leave dbghelp.h as is (Jose)

Cc: Jose Fonseca <jfonseca@vmware.com>
Cc: Brian Paul <brianp@vmware.com>
Cc: Alexander von Gluck IV <kallisti5@unixzen.com>
Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Jose Fonseca <jfonseca@vmware.com>