Disable MSVC warning C4828

"The file contains a character starting at offset 0x____ that is illegal
in the current source character set (____)."

These are caused by included third-party headers that are not UTF-8.
Hopefully their use of non-UTF-8 characters is limited to comments.

buildscripts/VisualStudio/MMCommon.props

@@ -23,7 +23,7 @@
   <ItemDefinitionGroup>
     <ClCompile>
       <WarningLevel>Level4</WarningLevel>
-      <DisableSpecificWarnings>4127;4290;%(DisableSpecificWarnings)</DisableSpecificWarnings>
+      <DisableSpecificWarnings>4127;4290;4828;%(DisableSpecificWarnings)</DisableSpecificWarnings>
       <ExceptionHandling>Sync</ExceptionHandling>
       <PreprocessorDefinitions>_CRT_SECURE_NO_WARNINGS;_SCL_SECURE_NO_WARNINGS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <MultiProcessorCompilation>true</MultiProcessorCompilation>