I think line 61 of XrExtensions.h should be #define FOR_EACH_SPATIAL_ANCHOR_EXPORT_FUNCTION(_) -
The projects don't build with the current version of the openxr-sdk source as XR_MSFT_spatial_anchor_export_preview is not defined - this means that FOR_EACH_SPATIAL_ANCHOR_EXPORT_FUNCTION is never defined (due to the cut & paste error) so the FOR_EACH_EXTENSION_FUNCTION macro definition is invalid .
I think line 61 of XrExtensions.h should be
#define FOR_EACH_SPATIAL_ANCHOR_EXPORT_FUNCTION(_)
-The projects don't build with the current version of the openxr-sdk source as XR_MSFT_spatial_anchor_export_preview is not defined - this means that FOR_EACH_SPATIAL_ANCHOR_EXPORT_FUNCTION is never defined (due to the cut & paste error) so the FOR_EACH_EXTENSION_FUNCTION macro definition is invalid .