Remove the c++default test

This test was the old way of checking whether to enable
c++11 functionality. That is now anyway required, so there
is no need for this test anymore.

Change-Id: I083e85a4698cac6bd9b573525c7b977f63e14113
Reviewed-by: Olivier Goffart (Woboq GmbH) <ogoffart@woboq.com>

config.tests/common/c++default/c++default.cpp

@@ -1 +0,0 @@
-__cplusplus

config.tests/common/c++default/c++default.pro

@@ -1,14 +0,0 @@
-TEMPLATE = aux
-CONFIG -= qt c++11
-PREPROCESSOR_SOURCES += c++default.cpp
-
-preprocessor.commands = $(CXX) $(CXXFLAGS) $(INCPATH) -o $@ -E $<
-msvc:preprocessor.commands = $(CXX) $(CXXFLAGS) $(INCPATH) -E ${QMAKE_FILE_IN} > ${QMAKE_FILE_OUT}
-preprocessor.output = ${QMAKE_FILE_BASE}.ii
-preprocessor.input = PREPROCESSOR_SOURCES
-preprocessor.variable_out = GENERATED_FILES
-QMAKE_EXTRA_COMPILERS += preprocessor
-
-all.target = all
-all.depends += c++default.ii
-QMAKE_EXTRA_TARGETS += all

configure

@@ -4427,21 +4427,6 @@ if $stdcxx_error && [ "$CFG_CONFIGURE_EXIT_ON_ERROR" = "yes" ]; then
     exit 101
 fi
 
-# Detect which edition of the C++ standard the compiler defaults to
-CFG_STDCXX_DEFAULT=199711
-if compileTest common/c++default "default C++ standard edition"; then
-    if [ -e "$outpath/config.tests/common/c++default/c++default.ii" ]; then
-        CFG_STDCXX_DEFAULT=`sed -n '/^[0-9]/s/L//p' "$outpath/config.tests/common/c++default/c++default.ii"`
-    else
-        if [ "$OPT_VERBOSE" = "yes" ]; then
-            echo "Failed to run the preprocessor, something is wrong with your compiler"
-        fi
-        if [ "$CFG_CONFIGURE_EXIT_ON_ERROR" = "yes" ]; then
-            exit 101
-        fi
-    fi
-fi
-
 # Detect whether 64-bit std::atomic works -- some 32-bit platforms require extra library support
 if compileTest common/atomic64 "64-bit std::atomic"; then
     CFG_ATOMIC64=yes
@@ -6941,7 +6926,6 @@ fi
 if [ -n "$RPATH_FLAGS" ]; then
     echo "QMAKE_RPATHDIR += $RPATH_FLAGS"
 fi
-echo "QT_COMPILER_STDCXX = $CFG_STDCXX_DEFAULT"
 if [ -n "$QT_GCC_MAJOR_VERSION" ]; then
     echo "QT_GCC_MAJOR_VERSION = $QT_GCC_MAJOR_VERSION"
     echo "QT_GCC_MINOR_VERSION = $QT_GCC_MINOR_VERSION"

mkspecs/features/default_pre.prf

@@ -8,7 +8,7 @@ CONFIG = \
     testcase_targets import_plugins import_qpa_plugin \
     $$CONFIG
 
-contains(QT_CONFIG, c++11):lessThan(QT_COMPILER_STDCXX, 201103): CONFIG += c++11
+CONFIG += c++11
 
 !build_pass:defined(QT_EDITION, var):!equals(QT_EDITION, "OpenSource"):!equals(QT_EDITION, "Preview") {
     #

tools/configure/configureapp.cpp

@@ -2388,22 +2388,6 @@ void Configure::autoDetection()
         }
     }
 
-    if (!dictionary["QMAKESPEC"].contains("msvc")) {
-        if (tryCompileProject("common/c++default", QString(), false)) {
-            QFile iiFile(buildPath + "/config.tests/common/c++default/c++default.ii");
-            if (iiFile.open(QIODevice::ReadOnly)) {
-                QString content = QString::fromUtf8(iiFile.readAll());
-                QRegExp expr("\\b([0-9]+)L\\b");
-                if (expr.indexIn(content) != -1)
-                    dictionary["CFG_STDCXX_DEFAULT"] = expr.cap(1);
-            }
-        }
-        if (dictionary["CFG_STDCXX_DEFAULT"].isEmpty()) {
-            cout << "Could not determine the C++ standard the compiler uses by default, assuming C++98." << endl;
-            dictionary["CFG_STDCXX_DEFAULT"] = "199711";
-        }
-    }
-
     if (dictionary["ATOMIC64"] == "auto")
         dictionary["ATOMIC64"] = checkAvailability("ATOMIC64") ? "yes" :
                                  checkAvailability("ATOMIC64-LIBATOMIC") ? "libatomic" : "no";
@@ -2756,8 +2740,6 @@ void Configure::generateOutputVars()
         qtConfig += "c++11 c++14";
     else if (dictionary[ "C++STD" ] == "c++1z")
         qtConfig += "c++11 c++14 c++1z";
-    if (!dictionary[ "CFG_STDCXX_DEFAULT" ].isEmpty())
-        qmakeVars += "QT_COMPILER_STDCXX = " + dictionary[ "CFG_STDCXX_DEFAULT" ];
 
     if (dictionary[ "USE_GOLD_LINKER" ] == "yes")
         qmakeConfig += "use_gold_linker";