diff --git a/Externals/libpng/CMakeLists.txt b/Externals/libpng/CMakeLists.txt
index b30749ee86..122007c7c5 100644
--- a/Externals/libpng/CMakeLists.txt
+++ b/Externals/libpng/CMakeLists.txt
@@ -18,4 +18,5 @@ set(SRCS
   pngwtran.c
   pngwutil.c
 )
+add_definitions(-Wno-self-assign)
 add_library(png STATIC ${SRCS})