windeployqt: MSVC: Add support for ARM64 hosts

Windeployqt deployed all the non Qt libraries in their x64
versions as it was not aware of the host it was running on. This
check needs to be done before any deployment happens.

Current support is limited for MSVC. mingw/clang might be done in
followup commits.

Pick-to: 6.7
Change-Id: I70fd6ad66c9cacfc6ff5b109f214a142b8b6d5f8
Reviewed-by: Joerg Bornemann <[email protected]>

src/tools/windeployqt/main.cpp

@@ -139,8 +139,10 @@ static Platform platformFromMkSpec(const QString &xSpec)
             return WindowsDesktopClangMsvc;
         if (xSpec.contains("arm"_L1))
             return WindowsDesktopMsvcArm;
+        if (xSpec.contains("G++"_L1))
+            return WindowsDesktopMinGW;
 
-        return xSpec.contains("g++"_L1) ? WindowsDesktopMinGW : WindowsDesktopMsvcIntel;
+        return WindowsDesktopMsvc;
     }
     return UnknownPlatform;
 }
@@ -1928,6 +1930,24 @@ int main(int argc, char **argv)
     }
 
     options.platform = platformFromMkSpec(xSpec);
+    // We are on MSVC and not crosscompiling. We need the host arch
+    if (options.platform == WindowsDesktopMsvc) {
+        SYSTEM_INFO si;
+        GetSystemInfo(&si);
+        switch (si.wProcessorArchitecture) {
+        case PROCESSOR_ARCHITECTURE_INTEL:
+        case PROCESSOR_ARCHITECTURE_IA64:
+        case PROCESSOR_ARCHITECTURE_AMD64:
+            options.platform |= IntelBased;
+            break;
+        case PROCESSOR_ARCHITECTURE_ARM:
+        case PROCESSOR_ARCHITECTURE_ARM64:
+            options.platform |= ArmBased;
+            break;
+        default:
+            options.platform = UnknownPlatform;
+        }
+    }
     if (options.platform == UnknownPlatform) {
         std::wcerr << "Unsupported platform " << xSpec << '\n';
         return 1;