Fix regression: Windows SDK 7.1 compiler detection

setenv.cmd from Windows SDk 7.1 automatically maps to a cross-compiler
and does not know /amd64.

Nothing to do for Windows SDK 8:
"...the Windows SDK no longer ships the following components:
  Windows SDK Platform Toolset
  Visual C++ Compilers and C Runtime (CRT)
  Windows SDK Configuration Tool"

Change-Id: Iade79631c4fd30f376c08b6dd9b47d174c0d9059
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Tobias Hunger <tobias.hunger@digia.com>

src/plugins/projectexplorer/msvctoolchain.cpp

@@ -467,19 +467,19 @@ QList<ToolChain *> MsvcToolChainFactory::autoDetect()
             tmp.append(new MsvcToolChain(generateDisplayName(name, MsvcToolChain::WindowsSDK, MsvcToolChain::x86),
                                          findAbiOfMsvc(MsvcToolChain::WindowsSDK, MsvcToolChain::x86, version),
                                          fi.absoluteFilePath(), QLatin1String("/x86"), true));
-            // Add all platforms
+            // Add all platforms, cross-compiler is automatically selected by SetEnv.cmd if needed
             tmp.append(new MsvcToolChain(generateDisplayName(name, MsvcToolChain::WindowsSDK, MsvcToolChain::amd64),
                                          findAbiOfMsvc(MsvcToolChain::WindowsSDK, MsvcToolChain::amd64, version),
-                                         fi.absoluteFilePath(), QLatin1String("/amd64"), true));
+                                         fi.absoluteFilePath(), QLatin1String("/x64"), true));
             tmp.append(new MsvcToolChain(generateDisplayName(name, MsvcToolChain::WindowsSDK, MsvcToolChain::x86_amd64),
                                          findAbiOfMsvc(MsvcToolChain::WindowsSDK, MsvcToolChain::x86_amd64, version),
-                                         fi.absoluteFilePath(), QLatin1String("/x86_amd64"), true));
+                                         fi.absoluteFilePath(), QLatin1String("/x64"), true));
             tmp.append(new MsvcToolChain(generateDisplayName(name, MsvcToolChain::WindowsSDK, MsvcToolChain::ia64),
                                          findAbiOfMsvc(MsvcToolChain::WindowsSDK, MsvcToolChain::ia64, version),
                                          fi.absoluteFilePath(), QLatin1String("/ia64"), true));
             tmp.append(new MsvcToolChain(generateDisplayName(name, MsvcToolChain::WindowsSDK, MsvcToolChain::x86_ia64),
                                          findAbiOfMsvc(MsvcToolChain::WindowsSDK, MsvcToolChain::x86_ia64, version),
-                                         fi.absoluteFilePath(), QLatin1String("/x86_ia64"), true));
+                                         fi.absoluteFilePath(), QLatin1String("/ia64"), true));
             // Make sure the default is front.
             if (folder == defaultSdkPath)
                 results = tmp + results;