SplineTest: an attempt to fix windows clang failure.
SplineTest: an attempt to fix windows clang failure.

3afea26bd251f4352b8cf9be7136f1622c7d8209 was ok,
607e29bfd0cd53af8d1b4d718036aff07aa47ce0 is bad.

darktable-org/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed,LebedevRI/rawspeed,LebedevRI/rawspeed,darktable-org/rawspeed