common arrow_flags: abbreviate some bitwise assignments

diff --git a/lib/common/arrows.c b/lib/common/arrows.c
index 4cdbf86841a39c6b81235ecb7654072e96682d8f..07e1cb89db188006825870747f75152f275e048a 100644 (file)
--- a/lib/common/arrows.c
+++ b/lib/common/arrows.c
@@ -235,8 +235,8 @@ void arrow_flags(Agedge_t * e, int *sflag, int *eflag)
        /* pick up arrowhead of opposing edge */
        f = agfindedge(agraphof(aghead(e)), aghead(e), agtail(e));
        arrow_flags(f, &s0, &e0);
-       *eflag = *eflag | s0;
-       *sflag = *sflag | e0;
+       *eflag |= s0;
+       *sflag |= e0;
     }
 }