OpenSubdiv: Fix crash caused by accessing OpenGL vendor from non-main thread

intern/opensubdiv/opensubdiv_capi.h

@@ -141,6 +141,7 @@ void openSubdiv_osdGLMeshDisplay(OpenSubdiv_GLMesh *gl_mesh,
 /* ** Utility functions ** */
 int openSubdiv_supportGPUDisplay(void);
 int openSubdiv_getAvailableEvaluators(void);
+void openSubdiv_init(void);
 void openSubdiv_cleanup(void);
 
 #ifdef __cplusplus

intern/opensubdiv/opensubdiv_utils_capi.cc

@@ -98,6 +98,12 @@ int openSubdiv_getAvailableEvaluators(void)
 	return flags;
 }
 
+void openSubdiv_init(void)
+{
+	/* Ensure all OpenGL strings are cached. */
+	(void)openSubdiv_getAvailableEvaluators();
+}
+
 void openSubdiv_cleanup(void)
 {
 	openSubdiv_osdGLDisplayDeinit();

source/blender/windowmanager/intern/wm_init_exit.c

@@ -191,6 +191,10 @@ void WM_init(bContext *C, int argc, const char **argv)
 		GPU_set_anisotropic(U.anisotropic_filter);
 		GPU_set_gpu_mipmapping(U.use_gpu_mipmap);
 
+#ifdef WITH_OPENSUBDIV
+		openSubdiv_init();
+#endif
+
 		UI_init();
 	}
 	else {