From 8aca1934ff43ff0fb6f4ea861c8bf47658a2aace Mon Sep 17 00:00:00 2001
From: "Paul E. Murphy" <pmur@users.noreply.github.com>
Date: Thu, 22 Aug 2019 10:08:01 -0500
Subject: [PATCH] libpng: update check for VSX enablement

The deprecated flag ENABLE_VSX should not be used to enable this
feature. Instead, use the baseline cpu feature set to determine.
---
 3rdparty/libpng/CMakeLists.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/3rdparty/libpng/CMakeLists.txt b/3rdparty/libpng/CMakeLists.txt
index c0c2b133cb..69bc754048 100644
--- a/3rdparty/libpng/CMakeLists.txt
+++ b/3rdparty/libpng/CMakeLists.txt
@@ -47,7 +47,9 @@ if(";${CPU_BASELINE_FINAL};" MATCHES "SSE2"
 endif()
 
 if(PPC64LE OR PPC64)
-  if(ENABLE_VSX AND NOT PPC64)
+  # VSX3 features are backwards compatible
+  if(";${CPU_BASELINE_FINAL};" MATCHES "VSX.*"
+      AND NOT PPC64)
     list(APPEND lib_srcs powerpc/powerpc_init.c powerpc/filter_vsx_intrinsics.c)
     add_definitions(-DPNG_POWERPC_VSX_OPT=2)
   else()