Fix vdb_view Windows build: include windows.h before GL/glu.h (#2247)

GL/glu.h uses APIENTRY without defining it. This previously compiled because
oneTBB (<= 2022.3) transitively included windows.h from its public headers;
oneTBB 2023.0 removed that include, so APIENTRY is no longer defined when
RenderModules.cc includes GL/glu.h. GL/glew.h cannot provide it either: it
undefines APIENTRY at the end of the header when it was the one defining it
(and the vcpkg glew package additionally patches out glew.h's internal
GL/glu.h include). Include windows.h explicitly before GL/glu.h instead of
relying on a transitive include.

Signed-off-by: Jonathan Swartz <jonathan@jswartz.info>

Author: swahtz

openvdb_cmd/vdb_view/RenderModules.cc

@@ -14,6 +14,13 @@
 #include <openvdb/util/Assert.h>
 
 #if defined(_WIN32)
+// GL/glu.h requires APIENTRY and CALLBACK from windows.h. GL/glew.h only defines
+// them temporarily (undefining them at the end of the header), so windows.h must
+// be included before GL/glu.h rather than relying on a transitive include.
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#include <windows.h>
 #include <GL/glu.h>
 #endif