OpenSubdiv: Fix for missing caching of vendor string parsing result

intern/opensubdiv/opensubdiv_capi.cc

@@ -304,6 +304,7 @@ int openSubdiv_supportGPUDisplay(void)
 		static bool vendor_checked = false;
 		static bool is_intel = false;
 		if (!vendor_checked) {
+			vendor_checked = true;
 			const char *vendor = (const char *)glGetString(GL_VENDOR);
 			if (strstr(vendor, "Intel")) {
 				if(getenv("OPENSUBDIV_ALLOW_INTEL") == NULL) {

intern/opensubdiv/opensubdiv_utils_capi.cc

@@ -78,6 +78,7 @@ int openSubdiv_getAvailableEvaluators(void)
 	 * hard time evaluating required shaders.
 	 */
 	if (!vendor_checked) {
+		vendor_checked = true;
 		const char *vendor = (const char *)glGetString(GL_VENDOR);
 		const char *renderer = (const char *)glGetString(GL_RENDERER);
 		if (strstr(vendor, "ATI") ||