Index: src/chext/chext.vc140.vcxproj
===================================================================
diff -u -r3d5880c6661c3ed500e0c1c739a923ae9ede0364 -red23794efb8acefdb3af5ab47c4be1bbde34cd90
--- src/chext/chext.vc140.vcxproj	(.../chext.vc140.vcxproj)	(revision 3d5880c6661c3ed500e0c1c739a923ae9ede0364)
+++ src/chext/chext.vc140.vcxproj	(.../chext.vc140.vcxproj)	(revision ed23794efb8acefdb3af5ab47c4be1bbde34cd90)
@@ -198,7 +198,7 @@
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-      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;_USRDLL;_CRT_SECURE_NO_DEPRECATE;_BIND_TO_CURRENT_VCLIBS_VERSION=1;NOMINMAX;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;_USRDLL;_CRT_SECURE_NO_DEPRECATE;_BIND_TO_CURRENT_VCLIBS_VERSION=1;NOMINMAX;_SILENCE_CXX17_CODECVT_HEADER_DEPRECATION_WARNING;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
       <PrecompiledHeader>Use</PrecompiledHeader>
@@ -211,6 +211,7 @@
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       <MultiProcessorCompilation>true</MultiProcessorCompilation>
       <AdditionalOptions>/Zm150 /Zc:threadSafeInit- %(AdditionalOptions)</AdditionalOptions>
+      <LanguageStandard>stdcpp17</LanguageStandard>
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     <ResourceCompile>
       <PreprocessorDefinitions>_DEBUG;%(PreprocessorDefinitions)</PreprocessorDefinitions>
@@ -233,7 +234,7 @@
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-      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;_USRDLL;_CRT_SECURE_NO_DEPRECATE;_BIND_TO_CURRENT_VCLIBS_VERSION=1;NOMINMAX;TESTING;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;_USRDLL;_CRT_SECURE_NO_DEPRECATE;_BIND_TO_CURRENT_VCLIBS_VERSION=1;NOMINMAX;TESTING;_SILENCE_CXX17_CODECVT_HEADER_DEPRECATION_WARNING;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
       <PrecompiledHeader>Use</PrecompiledHeader>
@@ -247,6 +248,7 @@
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       <MultiProcessorCompilation>true</MultiProcessorCompilation>
       <AdditionalOptions>/Zm150 /Zc:threadSafeInit- %(AdditionalOptions)</AdditionalOptions>
+      <LanguageStandard>stdcpp17</LanguageStandard>
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     <ResourceCompile>
       <PreprocessorDefinitions>_DEBUG;%(PreprocessorDefinitions)</PreprocessorDefinitions>
@@ -285,7 +287,7 @@
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-      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;_USRDLL;_CRT_SECURE_NO_DEPRECATE;_BIND_TO_CURRENT_VCLIBS_VERSION=1;NOMINMAX;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;_USRDLL;_CRT_SECURE_NO_DEPRECATE;_BIND_TO_CURRENT_VCLIBS_VERSION=1;NOMINMAX;_SILENCE_CXX17_CODECVT_HEADER_DEPRECATION_WARNING;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
       <PrecompiledHeader>Use</PrecompiledHeader>
@@ -298,6 +300,7 @@
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       <MultiProcessorCompilation>true</MultiProcessorCompilation>
       <AdditionalOptions>/Zm150 /Zc:threadSafeInit- %(AdditionalOptions)</AdditionalOptions>
+      <LanguageStandard>stdcpp17</LanguageStandard>
     </ClCompile>
     <ResourceCompile>
       <PreprocessorDefinitions>_DEBUG;%(PreprocessorDefinitions)</PreprocessorDefinitions>
@@ -321,7 +324,7 @@
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-      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;_USRDLL;_CRT_SECURE_NO_DEPRECATE;_BIND_TO_CURRENT_VCLIBS_VERSION=1;NOMINMAX;TESTING;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;_USRDLL;_CRT_SECURE_NO_DEPRECATE;_BIND_TO_CURRENT_VCLIBS_VERSION=1;NOMINMAX;TESTING;_SILENCE_CXX17_CODECVT_HEADER_DEPRECATION_WARNING;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <BasicRuntimeChecks>EnableFastChecks</BasicRuntimeChecks>
       <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
       <PrecompiledHeader>Use</PrecompiledHeader>
@@ -335,6 +338,7 @@
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       <MultiProcessorCompilation>true</MultiProcessorCompilation>
       <AdditionalOptions>/Zm150 /Zc:threadSafeInit- %(AdditionalOptions)</AdditionalOptions>
+      <LanguageStandard>stdcpp17</LanguageStandard>
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@@ -373,7 +377,7 @@
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       <InlineFunctionExpansion>OnlyExplicitInline</InlineFunctionExpansion>
-      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;_USRDLL;_CRT_SECURE_NO_DEPRECATE;_BIND_TO_CURRENT_VCLIBS_VERSION=1;NOMINMAX;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;_USRDLL;_CRT_SECURE_NO_DEPRECATE;_BIND_TO_CURRENT_VCLIBS_VERSION=1;NOMINMAX;_SILENCE_CXX17_CODECVT_HEADER_DEPRECATION_WARNING;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <StringPooling>true</StringPooling>
       <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
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@@ -386,6 +390,7 @@
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       <AdditionalOptions>/Zm150 /Zc:threadSafeInit- %(AdditionalOptions)</AdditionalOptions>
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+      <LanguageStandard>stdcpp17</LanguageStandard>
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@@ -409,7 +414,7 @@
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+      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;_USRDLL;_CRT_SECURE_NO_DEPRECATE;_BIND_TO_CURRENT_VCLIBS_VERSION=1;NOMINMAX;TESTING;_SILENCE_CXX17_CODECVT_HEADER_DEPRECATION_WARNING;%(PreprocessorDefinitions)</PreprocessorDefinitions>
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@@ -423,6 +428,7 @@
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       <AdditionalOptions>/Zm150 /Zc:threadSafeInit- %(AdditionalOptions)</AdditionalOptions>
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+      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;_USRDLL;_CRT_SECURE_NO_DEPRECATE;_BIND_TO_CURRENT_VCLIBS_VERSION=1;NOMINMAX;_SILENCE_CXX17_CODECVT_HEADER_DEPRECATION_WARNING;%(PreprocessorDefinitions)</PreprocessorDefinitions>
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@@ -474,6 +480,7 @@
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       <AdditionalOptions>/Zm150 /Zc:threadSafeInit- %(AdditionalOptions)</AdditionalOptions>
+      <LanguageStandard>stdcpp17</LanguageStandard>
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@@ -498,7 +505,7 @@
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+      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;_USRDLL;_CRT_SECURE_NO_DEPRECATE;_BIND_TO_CURRENT_VCLIBS_VERSION=1;NOMINMAX;TESTING;_SILENCE_CXX17_CODECVT_HEADER_DEPRECATION_WARNING;%(PreprocessorDefinitions)</PreprocessorDefinitions>
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@@ -511,6 +518,7 @@
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+      <LanguageStandard>stdcpp17</LanguageStandard>
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