Assume we are inside XBuild when MSBuildExtensionsPath32 contains "xbuild"

Jo Shields · Jo Shields · commit d995c590c2da · 2015-12-02T18:21:07.000Z
4.0/Mono.Posix.dll is not guaranteed to exist, on Mono 4.0+
diff --git a/lib/bootstrap/4.0/Microsoft.FSharp.Targets b/lib/bootstrap/4.0/Microsoft.FSharp.Targets
@@ -68,7 +68,7 @@ Copyright (C) Microsoft Corporation. Apache 2.0 License.
 
   <PropertyGroup>
     <UsingXBuild>false</UsingXBuild>
-    <UsingXBuild Condition="Exists('$(MSBuildExtensionsPath32)\..\4.0\Mono.Posix.dll')">true</UsingXBuild>
+    <UsingXBuild Condition="$(MSBuildExtensionsPath32.Contains('xbuild'))">true</UsingXBuild>
   </PropertyGroup>
 
   
diff --git a/src/fsharp/FSharp.Build/Microsoft.FSharp.Targets b/src/fsharp/FSharp.Build/Microsoft.FSharp.Targets
@@ -68,7 +68,7 @@ Copyright (C) Microsoft Corporation. Apache 2.0 License.
 
   <PropertyGroup>
     <UsingXBuild>false</UsingXBuild>
-    <UsingXBuild Condition="Exists('$(MSBuildExtensionsPath32)\..\4.0\Mono.Posix.dll')">true</UsingXBuild>
+    <UsingXBuild Condition="$(MSBuildExtensionsPath32.Contains('xbuild'))">true</UsingXBuild>
   </PropertyGroup>
 
     <Target
