1 files changed, 52 insertions, 3 deletions
diff --git a/configure.cmake b/configure.cmake
index 55c2d6b73c..f6fba22731 100644
--- a/configure.cmake
+++ b/configure.cmake
@@ -15,6 +15,54 @@ qt_find_package(Libudev PROVIDED_TARGETS PkgConfig::Libudev)
 
 #### Tests
 
+# c++14
+qt_config_compile_test(cxx14
+    LABEL "C++14 support"
+"#if __cplusplus > 201103L
+// Compiler claims to support C++14, trust it
+#else
+#  error __cplusplus must be > 201103L (the value of C++11)
+#endif
+
+
+int main(int argc, char **argv)
+{
+    (void)argc; (void)argv;
+    /* BEGIN TEST: */
+
+    /* END TEST: */
+    return 0;
+}
+"
+    CXX_STANDARD 14
+)
+
+# c++17
+qt_config_compile_test(cxx17
+    LABEL "C++17 support"
+"#if __cplusplus > 201402L
+// Compiler claims to support C++17, trust it
+#else
+#  error __cplusplus must be > 201402L (the value for C++14)
+#endif
+#include <map>  // https://bugs.llvm.org//show_bug.cgi?id=33117
+#include <variant>
+
+
+int main(int argc, char **argv)
+{
+    (void)argc; (void)argv;
+    /* BEGIN TEST: */
+std::variant<int> v(42);
+int i = std::get<int>(v);
+std::visit([](const auto &) { return 1; }, v);
+    /* END TEST: */
+    return 0;
+}
+"
+    CXX_STANDARD 17
+)
+
 # c++2a
 qt_config_compile_test(cxx2a
     LABEL "C++2a support"
@@ -33,7 +81,8 @@ int main(int argc, char **argv)
     /* END TEST: */
     return 0;
 }
-"# FIXME: qmake: CONFIG += c++11 c++14 c++17 c++2a
+"
+    CXX_STANDARD 20
 )
 
 # precompile_header
@@ -294,11 +343,11 @@ qt_feature("cxx11" PUBLIC
 )
 qt_feature("cxx14" PUBLIC
     LABEL "C++14"
-    CONDITION QT_FEATURE_cxx11 AND $<COMPILE_FEATURES:cxx_std_14>
+    CONDITION QT_FEATURE_cxx11 AND TEST_cxx14
 )
 qt_feature("cxx17" PUBLIC
     LABEL "C++17"
-    CONDITION QT_FEATURE_cxx14 AND $<COMPILE_FEATURES:cxx_std_17>
+    CONDITION QT_FEATURE_cxx14 AND TEST_cxx17
 )
 qt_feature("cxx1z" PUBLIC
     LABEL "C++17"