Added function returning build information to QLibraryInfo.

Useful for bug reports and test logs.

[ChangeLog][QtCore] QLibraryInfo provides information on how
Qt was built.

Change-Id: I867197fd7d2e10bcdf01a8eb47c9c1e03647e2c1
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/global/qlibraryinfo.cpp

@@ -255,6 +255,57 @@ QLibraryInfo::buildDate()
 }
 #endif //QT_NO_DATESTRING
 
+#if defined(Q_CC_CLANG) // must be before GNU, because clang claims to be GNU too
+#  ifdef __apple_build_version__ // Apple clang has other version numbers
+#    define COMPILER_STRING __clang_version__ " (Apple)"
+#  else
+#    define COMPILER_STRING __clang_version__
+#  endif
+#elif defined(Q_CC_GNU)
+#  define COMPILER_STRING "GCC " __VERSION__
+#elif defined(Q_CC_MSVC)
+#  if _MSC_VER < 1600
+#    define COMPILER_STRING "MSVC 2008"
+#  elif _MSC_VER < 1700
+#    define COMPILER_STRING "MSVC 2010"
+#  elif _MSC_VER < 1800
+#    define COMPILER_STRING "MSVC 2012"
+#  elif _MSC_VER < 1900
+#    define COMPILER_STRING "MSVC 2013"
+#  else
+#    define COMPILER_STRING "MSVC <unknown version>"
+#  endif
+#else
+#  define COMPILER_STRING "<unknown compiler>"
+#endif
+
+/*!
+  Returns a string describing how this version of Qt was built.
+
+  \internal
+
+  \since 5.3
+*/
+
+const char *QLibraryInfo::build()
+{
+   static const char data[] = "Qt " QT_VERSION_STR " (" __DATE__ "), "
+        COMPILER_STRING ", "
+#if QT_POINTER_SIZE == 4
+        "32"
+#else
+        "64"
+#endif
+        " bit, "
+#ifdef QT_NO_DEBUG
+        "release"
+#else
+        "debug"
+#endif
+        " build)";
+    return data;
+}
+
 /*!
     \since 5.0
     Returns \c true if this build of Qt was built with debugging enabled, or

src/corelib/global/qlibraryinfo.h

@@ -59,6 +59,8 @@ public:
     static QDate buildDate();
 #endif //QT_NO_DATESTRING
 
+    static const char * build();
+
     static bool isDebugBuild();
 
     enum LibraryLocation

tests/manual/qpainfo/main.cpp

@@ -116,10 +116,8 @@ int main(int argc, char **argv)
     QGuiApplication app(argc, argv);
 
     const QPlatformIntegration *platformIntegration = QGuiApplicationPrivate::platformIntegration();
-    std::cout << "Qt " << QT_VERSION_STR << " on \"" << QGuiApplication::platformName().toStdString() << "\" "
-              <<  QSysInfo::WordSize << " bit/"
+    std::cout << QLibraryInfo::build() << " on \"" << QGuiApplication::platformName().toStdString() << "\" "
               << (QSysInfo::ByteOrder == QSysInfo::LittleEndian ? "little endian" : "big endian") << '/'
-              << (QLibraryInfo::isDebugBuild() ? "debug" : "release")
               << '\n';
 
 #if defined(Q_OS_WIN)