configure: Check for basic cpp/winrt support

Some configurations (like MSVC2019 with c++20 on Windows 10) fail
to compile winrt/cpp headers as these include experimental
coroutines unconditionally. In these cases we can fall back to the
legacy implementation.

Pick-to: 6.2 6.3
Change-Id: Ibd574995f8ca1f865bbcdabede1ffcd0c340022f
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Ivan Solovev <ivan.solovev@qt.io>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

3 files changed, 31 insertions, 6 deletions

diff --git a/src/corelib/configure.cmake b/src/corelib/configure.cmake
index 107028bfac..96b580a0b6 100644
--- a/src/corelib/configure.cmake
+++ b/src/corelib/configure.cmake
@@ -460,6 +460,21 @@ closelog();
 }
 ")
 
+# cpp_winrt
+qt_config_compile_test(cpp_winrt
+    LABEL "cpp/winrt"
+    LIBRARIES
+        runtimeobject
+    CODE
+"// Including winrt/base.h causes an error in some configurations (Windows 10 SDK + c++20)
+#   include <winrt/base.h>
+
+int main(void)
+{
+    return 0;
+}
+")
+
 # xlocalescanprint
 qt_config_compile_test(xlocalescanprint
     LABEL "xlocale.h (or equivalents)"
@@ -706,6 +721,11 @@ qt_feature("xmlstream" PUBLIC
     LABEL "XML Streaming APIs"
     PURPOSE "Provides a simple streaming API for XML."
 )
+qt_feature("cpp-winrt" PRIVATE
+    LABEL "cpp/winrt base"
+    PURPOSE "basic cpp/winrt language projection support"
+    CONDITION WIN32 AND TEST_cpp_winrt
+)
 qt_feature_definition("xmlstream" "QT_NO_XMLSTREAM" NEGATE VALUE "1")
 qt_feature("xmlstreamreader" PUBLIC
     SECTION "Kernel"
@@ -924,6 +944,7 @@ qt_configure_add_summary_entry(ARGS "glib")
 qt_configure_add_summary_entry(ARGS "icu")
 qt_configure_add_summary_entry(ARGS "system-libb2")
 qt_configure_add_summary_entry(ARGS "mimetype-database")
+qt_configure_add_summary_entry(ARGS "cpp-winrt")
 qt_configure_add_summary_entry(
     TYPE "firstAvailableFeature"
     ARGS "etw lttng"
@@ -970,3 +991,8 @@ qt_configure_add_report_entry(
     MESSAGE "Qt requires poll(), ppoll(), poll_ts() or select() on this platform"
     CONDITION ( UNIX OR INTEGRITY ) AND ( NOT QT_FEATURE_poll_ppoll ) AND ( NOT QT_FEATURE_poll_pollts ) AND ( NOT QT_FEATURE_poll_poll ) AND ( NOT QT_FEATURE_poll_select )
 )
+qt_configure_add_report_entry(
+    TYPE WARNING
+    MESSAGE "Basic cpp/winrt support missing. Some features might not be available."
+    CONDITION MSVC AND NOT QT_FEATURE_cpp_winrt
+)
diff --git a/src/corelib/text/qlocale_win.cpp b/src/corelib/text/qlocale_win.cpp
index dafe441ee0..e5f5781208 100644
--- a/src/corelib/text/qlocale_win.cpp
+++ b/src/corelib/text/qlocale_win.cpp
@@ -53,7 +53,7 @@
 #   include <time.h>
 #endif
 
-#if defined(Q_CC_MSVC) && !defined(Q_CC_CLANG)
+#if QT_CONFIG(cpp_winrt) && !defined(Q_CC_CLANG)
 #   include <winrt/base.h>
 // Workaround for Windows SDK bug.
 // See https://github.com/microsoft/Windows.UI.Composition-Win32-Samples/issues/47
@@ -65,7 +65,7 @@ namespace winrt::impl
 #   include <winrt/Windows.Foundation.h>
 #   include <winrt/Windows.Foundation.Collections.h>
 #   include <winrt/Windows.System.UserProfile.h>
-#endif // defined(Q_CC_MSVC) && !defined(Q_CC_CLANG)
+#endif // QT_CONFIG(cpp_winrt) && !defined(Q_CC_CLANG)
 
 QT_BEGIN_NAMESPACE
 
@@ -694,16 +694,15 @@ QVariant QSystemLocalePrivate::toCurrencyString(const QSystemLocale::CurrencyToS
 QVariant QSystemLocalePrivate::uiLanguages()
 {
     QStringList result;
-#if defined(Q_CC_MSVC) && !defined(Q_CC_CLANG) // msvc supports WinRT calls
+#if QT_CONFIG(cpp_winrt) && !defined(Q_CC_CLANG)
     using namespace winrt;
-    using namespace Windows::Foundation;
     using namespace Windows::System::UserProfile;
     auto languages = GlobalizationPreferences::Languages();
     for (const auto &lang : languages)
         result << QString::fromStdString(winrt::to_string(lang));
     if (!result.isEmpty())
         return result; // else just fall back to WIN32 API implementation
-#endif // defined(Q_CC_MSVC) && !defined(Q_CC_CLANG)
+#endif // QT_CONFIG(cpp_winrt) && !defined(Q_CC_CLANG)
     // mingw and clang still have to use Win32 API
     unsigned long cnt = 0;
     QVarLengthArray<wchar_t, 64> buf(64);
diff --git a/src/plugins/networkinformation/networklistmanager/qnetworklistmanagerevents.h b/src/plugins/networkinformation/networklistmanager/qnetworklistmanagerevents.h
index 4c4625adb5..5bb2b2d9c0 100644
--- a/src/plugins/networkinformation/networklistmanager/qnetworklistmanagerevents.h
+++ b/src/plugins/networkinformation/networklistmanager/qnetworklistmanagerevents.h
@@ -51,7 +51,7 @@
 #include <wrl/wrappers/corewrappers.h>
 #include <comdef.h>
 
-#if defined(Q_CC_MSVC) && !defined(Q_CC_CLANG)
+#if QT_CONFIG(cpp_winrt) && !defined(Q_CC_CLANG)
 #define SUPPORTS_WINRT 1
 #endif