replace ingraphs header guard with more modern #pragma once

diff --git a/lib/ingraphs/ingraphs.h b/lib/ingraphs/ingraphs.h
index 0e435bd5c9dc1658424c5e4f94fa2472ea658775..ce63b61b6394fa536288b2cf666bb98866f3d21d 100644 (file)
--- a/lib/ingraphs/ingraphs.h
+++ b/lib/ingraphs/ingraphs.h
@@ -8,8 +8,7 @@
  * Contributors: Details at https://graphviz.org
  *************************************************************************/
 
-#ifndef INGRAPHS_H
-#define INGRAPHS_H
+#pragma once
 
 /* The ingraphs library works with libcgraph with all user-supplied data. For
  * this to work, the include file relies upon its context to supply a definition
@@ -54,4 +53,3 @@ extern "C" {
 #ifdef __cplusplus
 }
 #endif
-#endif