From cd49a63b7bcaee5b7f9e21f8a8e0440b7ee676b9 Mon Sep 17 00:00:00 2001
From: nick black <dankamongmen@gmail.com>
Date: Fri, 16 Jul 2021 00:00:58 -0400
Subject: [PATCH] only use MAP_SHARED_VALIDATE where defined #1941

---
 src/lib/png.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/lib/png.c b/src/lib/png.c
index 988bcebff..76f7f2c46 100644
--- a/src/lib/png.c
+++ b/src/lib/png.c
@@ -263,7 +263,11 @@ void* create_png_mmap(const ncvisual* ncv, size_t* bsize, int fd){
   }
   // FIXME hugetlb?
   void* map = mmap(NULL, mlen, PROT_WRITE | PROT_READ,
+#ifdef MAP_SHARED_VALIDATE
                    MAP_SHARED_VALIDATE |
+#else
+                   MAP_SHARED |
+#endif
                    (fd >= 0 ? 0 : MAP_ANONYMOUS), fd, 0);
   if(map == MAP_FAILED){
     logerror("Couldn't get %zuB map for %d\n", mlen, fd);