Remove --simpleresolution from other flags (#6193)

* Remove --simpleresolution from other flags

* Revert "Remove --simpleresolution from other flags"

This reverts commit d12c0fe25bd33c1087667f74926ca233ce3e9574.

* much simpler approach

src/fsharp/FSharp.Build/Microsoft.FSharp.NetSdk.targets

@@ -22,6 +22,7 @@ WARNING:  DO NOT MODIFY this file unless you are knowledgeable about MSBuild and
     <DefineCommonItemSchemas Condition=" '$(DefineCommonItemSchemas)' == '' ">true</DefineCommonItemSchemas>
     <DefineCommonReferenceSchemas Condition=" '$(DefineCommonReferenceSchemas)' == '' ">true</DefineCommonReferenceSchemas>
     <DefineCommonCapabilities Condition=" '$(DefineCommonCapabilities)' == '' ">true</DefineCommonCapabilities>
+    <SimpleResolution>true</SimpleResolution>
   </PropertyGroup>
 
   <ItemGroup Condition="'$(_DebugSymbolsProduced)' == 'true' and '$(PdbFile)' != ''">
@@ -39,7 +40,6 @@ WARNING:  DO NOT MODIFY this file unless you are knowledgeable about MSBuild and
     <TargetProfile Condition=" '$(TargetFrameworkIdentifier)' == '.NETFramework' " >mscorlib</TargetProfile>
     <TargetProfile Condition=" '$(TargetFrameworkIdentifier)' != '.NETFramework' " >netcore</TargetProfile>
     <TargetProfile Condition=" '$(TargetFrameworkIdentifier)' == '.NETStandard' and '$(_TargetFrameworkVersionWithoutV)' >= '2.0' " >netstandard</TargetProfile>
-    <OtherFlags>$(OtherFlags) --simpleresolution</OtherFlags>
   </PropertyGroup>
 
   <Import Project="Microsoft.FSharp.Targets" />

src/fsharp/FSharp.Build/Microsoft.FSharp.Targets

@@ -266,6 +266,12 @@ this file.
             <EmbeddedFiles Include="@(Embed)" KeepDuplicates="false" />
         </ItemGroup>
 
+        <!-- Dotnet SDK requires SimpleResolution to be true Legacy project system build not -->
+        <PropertyGroup>
+            <FscOtherFlags Condition="'$(SimpleResolution)' == 'true'">--simpleresolution $(OtherFlags)</FscOtherFlags>
+            <FscOtherFlags Condition="'$(SimpleResolution)' != 'true'">$(OtherFlags)</FscOtherFlags>
+        </PropertyGroup>
+
         <!-- Condition is to filter out the _CoreCompileResourceInputs so that it doesn't pass in culture resources to the compiler -->
         <!-- NOTE: ManifestResourceWithNoCulture and ManifestNonResxWithNoCultureOnDisk are generated by Mono targets files --> 
         <Fsc  Condition=" '%(_CoreCompileResourceInputs.WithCulture)' != 'true' "
@@ -286,7 +292,7 @@ this file.
               LCID="$(LCID)"
               NoFramework="true"
               Optimize="$(Optimize)"
-              OtherFlags="$(OtherFlags)"
+              OtherFlags="$(FscOtherFlags)"
               OutputAssembly="@(IntermediateAssembly)"
               PdbFile="$(PdbFile)"
               Platform="$(PlatformTarget)"