5 files changed, 66 insertions, 13 deletions
diff --git a/src/corelib/global/qfloat16.h b/src/corelib/global/qfloat16.h
index a8befd7adb..766ab319a4 100644
--- a/src/corelib/global/qfloat16.h
+++ b/src/corelib/global/qfloat16.h
@@ -67,11 +67,9 @@ QT_BEGIN_NAMESPACE
 class qfloat16
 {
 public:
-#ifndef Q_QDOC
     Q_DECL_CONSTEXPR inline qfloat16() Q_DECL_NOTHROW : b16(0) { }
     inline qfloat16(float f) Q_DECL_NOTHROW;
     inline operator float() const Q_DECL_NOTHROW;
-#endif
 
 private:
     quint16 b16;
diff --git a/src/corelib/global/qglobal.cpp b/src/corelib/global/qglobal.cpp
index 5c1665fa00..14fb4e77da 100644
--- a/src/corelib/global/qglobal.cpp
+++ b/src/corelib/global/qglobal.cpp
@@ -2142,11 +2142,20 @@ struct QUnixOSVersion
 
 static QString unquote(const char *begin, const char *end)
 {
+    // man os-release says:
+    // Variable assignment values must be enclosed in double
+    // or single quotes if they include spaces, semicolons or
+    // other special characters outside of A–Z, a–z, 0–9. Shell
+    // special characters ("$", quotes, backslash, backtick)
+    // must be escaped with backslashes, following shell style.
+    // All strings should be in UTF-8 format, and non-printable
+    // characters should not be used. It is not supported to
+    // concatenate multiple individually quoted strings.
     if (*begin == '"') {
         Q_ASSERT(end[-1] == '"');
-        return QString::fromLatin1(begin + 1, end - begin - 2);
+        return QString::fromUtf8(begin + 1, end - begin - 2);
     }
-    return QString::fromLatin1(begin, end - begin);
+    return QString::fromUtf8(begin, end - begin);
 }
 static QByteArray getEtcFileContent(const char *filename)
 {
@@ -3243,6 +3252,34 @@ void *qMemSet(void *dest, int c, size_t n) { return memset(dest, c, n); }
 // add thread-safety for the Qt wrappers.
 static QBasicMutex environmentMutex;
 
+/*
+  Wraps tzset(), which accesses the environment, so should only be called while
+  we hold the lock on the environment mutex.
+*/
+void qTzSet()
+{
+    QMutexLocker locker(&environmentMutex);
+#if defined(Q_OS_WIN)
+    _tzset();
+#else
+    tzset();
+#endif // Q_OS_WIN
+}
+
+/*
+  Wrap mktime(), which is specified to behave as if it called tzset(), hence
+  shares its implicit environment-dependence.
+*/
+time_t qMkTime(struct tm *when)
+{
+    QMutexLocker locker(&environmentMutex);
+    return mktime(when);
+}
+
+// Also specified to behave as if they call tzset():
+// localtime() -- but not localtime_r(), which we use when threaded
+// strftime() -- not used (except in tests)
+
 /*!
     \relates <QtGlobal>
     \threadsafe
diff --git a/src/corelib/global/qglobal.h b/src/corelib/global/qglobal.h
index b608489576..8680742c94 100644
--- a/src/corelib/global/qglobal.h
+++ b/src/corelib/global/qglobal.h
@@ -591,11 +591,11 @@ Q_DECL_CONSTEXPR inline qint64 qRound64(float d)
 { return d >= 0.0f ? qint64(d + 0.5f) : qint64(d - float(qint64(d-1)) + 0.5f) + qint64(d-1); }
 
 template <typename T>
-Q_DECL_CONSTEXPR inline const T &qMin(const T &a, const T &b) { return (a < b) ? a : b; }
+constexpr inline const T &qMin(const T &a, const T &b) { return (a < b) ? a : b; }
 template <typename T>
-Q_DECL_CONSTEXPR inline const T &qMax(const T &a, const T &b) { return (a < b) ? b : a; }
+constexpr inline const T &qMax(const T &a, const T &b) { return (a < b) ? b : a; }
 template <typename T>
-Q_DECL_CONSTEXPR inline const T &qBound(const T &min, const T &val, const T &max)
+constexpr inline const T &qBound(const T &min, const T &val, const T &max)
 { return qMax(min, qMin(max, val)); }
 
 #ifndef Q_FORWARD_DECLARE_OBJC_CLASS
@@ -1005,6 +1005,15 @@ QForeachContainer<typename std::decay<T>::type> qMakeForeachContainer(T &&t)
 }
 
 }
+
+#if __cplusplus >= 201703L
+// Use C++17 if statement with initializer. User's code ends up in a else so
+// scoping of different ifs is not broken
+#define Q_FOREACH(variable, container)                                   \
+for (auto _container_ = QtPrivate::qMakeForeachContainer(container);     \
+     _container_.i != _container_.e;  ++_container_.i)                   \
+    if (variable = *_container_.i; false) {} else
+#else
 // Explanation of the control word:
 //  - it's initialized to 1
 //  - that means both the inner and outer loops start
@@ -1019,7 +1028,7 @@ for (auto _container_ = QtPrivate::qMakeForeachContainer(container); \
      _container_.control && _container_.i != _container_.e;         \
      ++_container_.i, _container_.control ^= 1)                     \
     for (variable = *_container_.i; _container_.control; _container_.control = 0)
-
+#endif
 #endif // QT_NO_FOREACH
 
 #define Q_FOREVER for(;;)
@@ -1186,9 +1195,6 @@ namespace QtPrivate {
 //like std::enable_if
 template <bool B, typename T = void> struct QEnableIf;
 template <typename T> struct QEnableIf<true, T> { typedef T Type; };
-
-template <bool B, typename T, typename F> struct QConditional { typedef T Type; };
-template <typename T, typename F> struct QConditional<false, T, F> { typedef F Type; };
 }
 
 QT_END_NAMESPACE
diff --git a/src/corelib/global/qglobal_p.h b/src/corelib/global/qglobal_p.h
index 0f092e9006..d52f6268e4 100644
--- a/src/corelib/global/qglobal_p.h
+++ b/src/corelib/global/qglobal_p.h
@@ -61,6 +61,16 @@
 #endif
 
 #if defined(__cplusplus)
+#include <time.h>
+
+QT_BEGIN_NAMESPACE
+
+// These behave as if they consult the environment, so need to share its locking:
+Q_CORE_EXPORT void qTzSet();
+Q_CORE_EXPORT time_t qMkTime(struct tm *when);
+
+QT_END_NAMESPACE
+
 #if !QT_HAS_BUILTIN(__builtin_available)
 #include <initializer_list>
 #include <QtCore/qoperatingsystemversion.h>
diff --git a/src/corelib/global/qnamespace.h b/src/corelib/global/qnamespace.h
index dec2c44637..41b94bf15a 100644
--- a/src/corelib/global/qnamespace.h
+++ b/src/corelib/global/qnamespace.h
@@ -516,7 +516,7 @@ public:
         AA_SetPalette = 19,
         AA_EnableHighDpiScaling = 20,
         AA_DisableHighDpiScaling = 21,
-        AA_UseStyleSheetPropagationInWidgetStyles = 22, // ### Qt 6: remove me
+        AA_UseStyleSheetPropagationInWidgetStyles = 22,
         AA_DontUseNativeDialogs = 23,
         AA_SynthesizeMouseForUnhandledTabletEvents = 24,
         AA_CompressHighFrequencyEvents = 25,
@@ -1504,9 +1504,11 @@ public:
         // Metadata
         FontRole = 6,
         TextAlignmentRole = 7,
+#if QT_DEPRECATED_SINCE(5, 13)
         BackgroundColorRole = 8,
-        BackgroundRole = 8,
         TextColorRole = 9,
+#endif
+        BackgroundRole = 8,
         ForegroundRole = 9,
         CheckStateRole = 10,
         // Accessibility