Make QSysInfo enum types available cross-platform

This makes the WinVersion and MacVersion enums accessible in platform
indepedent code to avoid the need to use #ifdef Q_OS_* chains in
user code, leading to fewer platform-dependent code paths and better
maintainability.

To indicate "this is not a Windows based OS" a enum value
QSysInfo::WV_None (with value 0x0000) in QSysInfo::WinVersion
is introduced. This keeps the WV_*_based masks usable.

To indicate "this is not a Darwin based OS" a enum values
QSysInfo::MV_None (with value 0xffff) in QSysInfo::MacVersion
is introduced. 0x0000 might have been preferable for (not so
important "consitency" with QSysInfo::WV_None), but is already
taken by QSysInfo::MV_Unknown with a different meaning.

Change-Id: Ib395e0efba58558f31f4e0806f7333165aa90aa5
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/global/qglobal.cpp

@@ -985,9 +985,9 @@ bool qSharedBuild() Q_DECL_NOTHROW
     \li \l ByteOrder specifies whether the platform is big-endian or
        little-endian.
     \li \l WindowsVersion specifies the version of the Windows operating
-       system on which the application is run (Windows only)
+       system on which the application is run.
     \li \l MacintoshVersion specifies the version of the Macintosh
-       operating system on which the application is run (Mac only).
+       operating system on which the application is run.
     \endlist
 
     Some constants are defined only on certain platforms. You can use
@@ -1010,7 +1010,7 @@ bool qSharedBuild() Q_DECL_NOTHROW
 /*!
     \variable QSysInfo::WindowsVersion
     \brief the version of the Windows operating system on which the
-           application is run (Windows only)
+           application is run.
 */
 
 /*!
@@ -1018,19 +1018,22 @@ bool qSharedBuild() Q_DECL_NOTHROW
     \since 4.4
 
     Returns the version of the Windows operating system on which the
-    application is run (Windows only).
+    application is run, or WV_None if the operating system is not
+    Windows.
 */
 
 /*!
     \variable QSysInfo::MacintoshVersion
     \brief the version of the Macintosh operating system on which
-           the application is run (Mac only).
+           the application is run.
 */
 
 /*!
     \fn QSysInfo::MacVersion QSysInfo::macVersion()
 
-    Returns the version of Darwin (OS X or iOS) on which the application is run.
+    Returns the version of Darwin (OS X or iOS) on which the
+    application is run, or MV_None if the operating system
+    is not a version of Darwin.
 */
 
 /*!
@@ -1093,6 +1096,8 @@ bool qSharedBuild() Q_DECL_NOTHROW
     \value WV_NT_based  NT-based version of Windows
     \value WV_CE_based  CE-based version of Windows
 
+    \value WV_None Operating system other than Windows.
+
     \sa MacVersion
 */
 
@@ -1140,6 +1145,8 @@ bool qSharedBuild() Q_DECL_NOTHROW
     \value MV_IOS_7_1  iOS 7.1
     \value MV_IOS_8_0  iOS 8.0
 
+    \value MV_None     Not a Darwin operating system
+
     \sa WinVersion
 */
 

src/corelib/global/qsysinfo.h

@@ -72,8 +72,9 @@ public:
 #  endif
     };
 #endif
-#if defined(Q_OS_WIN) || defined(Q_OS_CYGWIN)
     enum WinVersion {
+        WV_None     = 0x0000,
+
         WV_32s      = 0x0001,
         WV_95       = 0x0002,
         WV_98       = 0x0003,
@@ -107,14 +108,18 @@ public:
         WV_CE_6     = 0x0400,
         WV_CE_based = 0x0f00
     };
+#if defined(Q_OS_WIN) || defined(Q_OS_CYGWIN)
     static const WinVersion WindowsVersion;
     static WinVersion windowsVersion();
-
+#else
+    static const WinVersion WindowsVersion = WV_None;
+    static WinVersion windowsVersion() { return WV_None; }
 #endif
-#ifdef Q_OS_MAC
+
-#  define Q_MV_OSX(major, minor) (major == 10 ? minor + 2 : (major == 9 ? 1 : 0))
+#define Q_MV_OSX(major, minor) (major == 10 ? minor + 2 : (major == 9 ? 1 : 0))
-#  define Q_MV_IOS(major, minor) (QSysInfo::MV_IOS | major << 4 | minor)
+#define Q_MV_IOS(major, minor) (QSysInfo::MV_IOS | major << 4 | minor)
     enum MacVersion {
+        MV_None    = 0xffff,
         MV_Unknown = 0x0000,
 
         /* version */
@@ -155,8 +160,12 @@ public:
         MV_IOS_7_1 = Q_MV_IOS(7, 1),
         MV_IOS_8_0 = Q_MV_IOS(8, 0)
     };
+#if defined(Q_OS_MAC)
     static const MacVersion MacintoshVersion;
     static MacVersion macVersion();
+#else
+    static const MacVersion MacintoshVersion = MV_None;
+    static MacVersion macVersion() { return MV_None; }
 #endif
 
     static QString buildCpuArchitecture();