* [lpng] Adjustment: Update libpng to version 1.6.37.

Engine/lib/lpng/projects/vstudio/README.txt

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+Instructions for building libpng using Microsoft Visual Studio
+==============================================================
+
+Copyright (c) 2018 Cosmin Truta
+Copyright (c) 2010,2013,2015 Glenn Randers-Pehrson
+
+This code is released under the libpng license.
+For conditions of distribution and use, see the disclaimer and license
+in png.h
+
+This directory contains a solution for building libpng under Microsoft
+Visual Studio 2010.  It may also work under later versions of Visual
+Studio.  You should be familiar with Visual Studio before using this
+solution.
+
+Initial preparations
+--------------------
+You must enter some information in zlib.props before attempting to
+build with this 'solution'.  Please read and edit zlib.props first.
+You will probably not be familiar with the contents of zlib.props -
+do not worry, it is mostly harmless.
+
+This is all you need to do to build the 'release' and 'release library'
+configurations.
+
+Debugging
+---------
+The release configurations default to /Ox optimization.  Full debugging
+information is produced (in the .pdb), but if you encounter a problem
+the optimization may make it difficult to debug.  Simply rebuild with a
+lower optimization level (e.g. /Od.)
+
+Linking your application
+------------------------
+Normally you should link against the 'release' configuration.  This
+builds a DLL for libpng with the default runtime options used by Visual
+Studio.  In particular the runtime library is the "MultiThreaded DLL"
+version.  If you use Visual Studio defaults to build your application,
+you should have no problems.
+
+If you don't use the Visual Studio defaults your application must still
+be built with the default runtime option (/MD).  If, for some reason,
+it is not then your application will crash inside libpng16.dll as soon
+as libpng tries to read from a file handle you pass in.
+
+If you do not want to use the DLL, and prefer static linking instead,
+you may choose the 'release library' configuration.  This is built with
+a non-standard runtime library - the "MultiThreaded" version.  When you
+build your application, it must be compiled with this option (/MT),
+otherwise it will not build (if you are lucky) or it will crash (if you
+are not.) See the WARNING file that is distributed with this README.
+
+Stop reading here
+-----------------
+You have enough information to build a working application.
+
+Debug versions have limited support
+-----------------------------------
+This solution includes limited support for debug versions of libpng.
+You do not need these unless your own solution itself uses debug builds
+(it is far more effective to debug on the release builds, there is no
+point building a special debug build unless you have heap corruption
+problems that you can't track down.)
+
+The debug build of libpng is minimally supported.  Support for debug
+builds of zlib is also minimal.  Please keep this in mind, if you want
+to use it.
+
+WARNING
+-------
+Libpng 1.6.x does not use the default run-time library when building
+static library builds of libpng; instead of the shared DLL runtime, it
+uses a static runtime.  If you need to change this, make sure to change
+the setting on all the relevant projects:
+
+    libpng
+    zlib
+    all the test programs
+
+The runtime library settings for each build are as follows:
+
+               Release        Debug
+    DLL         /MD            /MDd
+    Library     /MT            /MTd
+
+Also, be sure to build libpng, zlib, and your project, all for the same
+platform (e.g., 32-bit or 64-bit).

Engine/lib/lpng/projects/vstudio/zlib.props

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+<?xml version="1.0" encoding="utf-8"?>
+<!--
+ * zlib.props - location of zlib source
+ *
+ * Copyright (c) 2018 Cosmin Truta
+ * Copyright (c) 1998-2011 Glenn Randers-Pehrson
+ *
+ * This code is released under the libpng license.
+ * For conditions of distribution and use, see the disclaimer
+ * and license in png.h
+
+ * You may need to edit this file in order to update the location
+ * of the zlib source code.
+ -->
+
+<Project ToolsVersion="4.0"
+   xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup Label="Globals">
+    <!-- Place the name of the directory containing the source of zlib used for
+	 debugging in this property.
+
+         The directory need only contain the '.c' and '.h' files from the
+	 source.
+
+	 If you use a relative directory name (as below) then it must be
+	 relative to the project directories; these are one level deeper than
+	 the directories containing this file.
+
+	 If the version of zlib you use does not match that used when the
+	 distribution was built you will get warnings from pngtest that the zlib
+	 versions do not match.  The zlib version used in this build is recorded
+	 below:
+     -->
+    <ZLibSrcDir>..\..\..\..\zlib</ZLibSrcDir>
+
+    <!-- The following line allows compilation for an ARM target with Visual
+         Studio 2012.  Notice that this is not supported by the Visual Studio
+         2012 IDE and that the programs that result cannot be run unless they
+         signed by Microsoft.  This is therefore untested; only Microsoft can
+         test it:
+     -->
+    <WindowsSDKDesktopARMSupport>true</WindowsSDKDesktopARMSupport>
+
+    <!-- The following lines provide a global (solution level) control of the
+         warnings issued by the compiler, these are used in the individual
+         project files (*/*.vcxproj) with, for zlib, some extra disables.
+
+         Different versions of Visual Studio may require different settings,
+         these settings work with Visual Studio 2013.  Just set
+         TreatWarningAsError to false to check the build without failing on
+         errors.
+     -->
+   <WarningLevel>EnableAllWarnings</WarningLevel>
+   <TreatWarningAsError>true</TreatWarningAsError>
+   <DisableSpecificWarnings>4255;4668;4710;4711;4746;4820;4996</DisableSpecificWarnings>
+  </PropertyGroup>
+</Project>