Updating the MSBuildTasks to properly emit PathMap when generating the response commands.

src/Compilers/Core/MSBuildTask/ManagedCompiler.cs

@@ -636,6 +636,7 @@ protected internal virtual void AddResponseFileCommands(CommandLineBuilderExtens
             commandLine.AppendWhenTrue("/nowin32manifest", _store, nameof(NoWin32Manifest));
             commandLine.AppendPlusOrMinusSwitch("/optimize", _store, nameof(Optimize));
             commandLine.AppendPlusOrMinusSwitch("/deterministic", _store, nameof(Deterministic));
+            commandLine.AppendSwitchIfNotNull("/pathmap:", PathMap);
             commandLine.AppendSwitchIfNotNull("/out:", OutputAssembly);
             commandLine.AppendSwitchIfNotNull("/ruleset:", CodeAnalysisRuleSet);
             commandLine.AppendSwitchIfNotNull("/errorlog:", ErrorLog);

src/Compilers/Core/MSBuildTaskTests/CscTests.cs

@@ -33,7 +33,7 @@ public void PathMapOption()
             var csc = new Csc();
             csc.Sources = MSBuildUtil.CreateTaskItems("test.cs");
             csc.PathMap = "K1=V1,K2=V2";
-            Assert.Equal("/pathmap:\"K1=V1,K2=V2\" /out:test.exe test.cs", csc.GenerateResponseFileContents());
+            Assert.Equal("/pathmap:K1=V1,K2=V2 /out:test.exe test.cs", csc.GenerateResponseFileContents());
 
             csc = new Csc();
             csc.Sources = MSBuildUtil.CreateTaskItems("test.cs");

src/Compilers/Core/MSBuildTaskTests/VbcTests.cs

@@ -30,7 +30,7 @@ public void PathMapOption()
             var vbc = new Vbc();
             vbc.Sources = MSBuildUtil.CreateTaskItems("test.vb");
             vbc.PathMap = "K1=V1,K2=V2";
-            Assert.Equal("/optionstrict:custom /pathmap:\"K1=V1,K2=V2\" /out:test.exe test.vb", vbc.GenerateResponseFileContents());
+            Assert.Equal("/optionstrict:custom /pathmap:K1=V1,K2=V2 /out:test.exe test.vb", vbc.GenerateResponseFileContents());
 
             vbc = new Vbc();
             vbc.Sources = MSBuildUtil.CreateTaskItems("test.vb");