Easier to just make g-ir-scanner skip this header via #ifndef __GI_SCANNER__
than maintain different sets of headers in the meson.build file.
Warning: Gst: symbol="rint": Unknown namespace for symbol "rint"
Warning: Gst: symbol="rintf": Unknown namespace for symbol "rintf"
Warning: Gst: symbol="isnan": Unknown namespace for symbol "isnan"
Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/579>
Visual C++ does not have isnan(), so add fallback to
math-compat.h (could use _isnan() in this case, but
this makes it work for all cases where isnan is missing).
https://bugzilla.gnome.org/show_bug.cgi?id=679112
Add minimal math-compath.h header where we can define fallback
versions for miscellaneous math functions that aren't always
available, so we don't have to duplicate this in plugins.
The header is not included by default, so needs to be
included explicitly for now.
https://bugzilla.gnome.org/show_bug.cgi?id=630802
