fix: MSB4185: The function "IsWindows" on type "System.OperatingSystem" is not available (#4160)

* fix: MSB4185: The function "IsWindows" on type "System.OperatingSystem" is not available

Resolves #4141:
- #4141

When building .NET Framework applications, only whitelisted `System.*` property function invocations (e.g., `System.OperatingSystem.IsWindows()` are allowed).

This PR avoid using an unlisted functions in the transitive build targets.

---------

Co-authored-by: Allan Ritchie <allan.ritchie@gmail.com>
Co-authored-by: Martin Costello <martin@martincostello.com>

Author: 3 people

CHANGELOG.md

@@ -10,6 +10,7 @@
 ### Fixes
 
 - Work around iOS SHA1 bug ([#4143](https://github.com/getsentry/sentry-dotnet/pull/4143))
+- Fixes build error when building .NET Framework applications using Sentry 5.6.0: `MSB4185 :The function "IsWindows" on type "System.OperatingSystem" is not available` ([#4160](https://github.com/getsentry/sentry-dotnet/pull/4160))
 
 ### Dependencies
 

src/Sentry/buildTransitive/Sentry.targets

@@ -15,7 +15,7 @@
     <Error Text="Android projects using Sentry cannot build using AndroidEnableAssemblyCompression = false due to a Microsoft issue.  Please follow https://github.com/dotnet/android/issues/9752" />
   </Target>
 
-  <ItemGroup Condition="$([System.OperatingSystem]::IsWindows())">
+  <ItemGroup Condition="$([MSBuild]::IsOSPlatform('Windows'))">
     <!-- See: https://github.com/getsentry/sentry-dotnet/pull/4111 -->
     <LinkerArg Include="/NODEFAULTLIB:MSVCRT" />
   </ItemGroup>