Doc: Update supported platforms for Qt 5.9

  - Drop macOS 10.9, iOS 7, WinRT 8.1, Windows Phone 8.1
  - Add MSVC 2017 for Windows configurations

Also clarify the latest Qt version on the top-level supported
platforms page.

Change-Id: Ia5b193c8cfbed67ec50e4951d6f474b6b19f4e8e
Reviewed-by: Jake Petroules <jake.petroules@qt.io>

doc/config/qtdoc.qdocconf

@@ -122,3 +122,4 @@ qhp.QtDoc.extraFiles         += images/qt-codesample.png
 HTML.stylesheets             += style/qt5-sidebar.html
 
 macro.indextitle              = "\\title Qt $QT_VER"
+macro.qtver                   = "$QT_VER"

doc/src/platforms/supported-platforms.qdoc

@@ -58,7 +58,10 @@
     A \e {configuration} is a combination of an operating system version,
     a compiler version, and a graphics system.
 
+    \b {Supported configurations for Qt \qtver}
+
     \include supported-platforms.qdocinc latest
+
     In the above table, the configurations in \b bold are \e {reference
     configurations}.
 

doc/src/platforms/supported-platforms.qdocinc

@@ -39,10 +39,86 @@ Mobile Platforms: \l {Qt for Android}{Android},
 //! [mobile]
 
 //! [all]
+\section1 Qt 5.9
+\b {Supported until one year after release}
+
+//! [5.9] //! [latest]
+
+    \table 80%
+    \header \li Platform \li Compiler \li Notes
+    \header \li {3,1} \l {Qt for Windows}{Windows}
+    \row \li Windows 10 (64-bit)
+         \li MSVC 2017, \b {MSVC 2015}, MSVC 2013, MinGW 5.3
+         \li
+    \row \li Windows 10 (32-bit)
+         \li MSVC 2017, \b {MSVC 2015}, MSVC 2013, MinGW 5.3
+         \li
+    \row \li Windows 8.1 (64-bit)
+         \li MSVC 2017, MSVC 2015, \b {MSVC 2013}, MinGW 5.3
+         \li
+    \row \li Windows 8.1 (32-bit)
+         \li MSVC 2017, MSVC 2015, \b {MSVC 2013}, MinGW 5.3
+         \li
+    \row \li Windows 7 (64-bit)
+         \li MSVC 2017, MSVC 2015, MSVC 2013, \b {MinGW 5.3}
+         \li
+    \row \li Windows 7 (32-bit)
+         \li MSVC 2017, MSVC 2015, MSVC 2013, MinGW 5.3
+         \li \l{https://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win32/Personal%20Builds/mingw-builds/5.3.0/threads-posix/dwarf/i686-5.3.0-release-posix-dwarf-rt_v4-rev0.7z/download}{MinGW-builds gcc 5.3.0 (32-bit)}
+
+    \row \li {3,1} \header \li {3,1} \l {Qt for Linux/X11}{Linux/X11}
+    \row \li openSUSE 42.1 (64-bit)
+         \li \b {GCC 4.8.5}
+         \li
+    \row \li Red Hat Enterprise Linux 6.6 (64-bit)
+         \li \b {GCC 4.9.1}
+         \li devtoolset-3
+    \row \li Red Hat Enterprise Linux 7.2 (64-bit)
+         \li \b {GCC 5.3.1}
+         \li devtoolset-4
+    \row \li Ubuntu 14.04 (64-bit)
+         \li GCC 4.8.2
+         \li Ubuntu 4.8.2-19ubuntu1
+    \row \li Ubuntu 16.04 (64-bit)
+         \li \b {GCC as provided by Canonical}
+         \li
+    \row \li (Linux 32/64-bit)
+         \li GCC 4.8, GCC 4.9, GCC 5.3
+         \li
+
+    \row \li {3,1} \header \li {3,1} \l {Qt for macOS}{\macos}
+    \row \li \macos \b 10.10, \b 10.11, \b 10.12
+         \li \b {Clang as provided by Apple}
+         \li
+
+    \row \li {3,1} \header \li {3,1}
+         Embedded Platforms: \l {Qt for Embedded Linux}{Embedded Linux}, \l {QNX}
+    \row \li \l {Qt for Embedded Linux}{Embedded Linux}
+         \li GCC \li ARM Cortex-A, Intel boards with GCC-based toolchains
+    \row \li QNX 6.6.0, 7.0 (armv7le and x86)
+         \li \b {QCC as provided by QNX)
+         \li Hosts: \b {RHEL 6.6 (64-bit)}, \b {RHEL 7.2 (64-bit)}, Windows
+
+    \row \li {3,1} \header \li {3,1}
+          Mobile Platforms: \l {Qt for Android}{Android}, \l {Qt for iOS}{iOS},
+          Ubuntu Touch, Universal Windows Platform (UWP)
+    \row \li Universal Windows Platform (UWP) (x86, \b x86_64, armv7)
+         \li \b {MSVC 2017}, \b {MSVC 2015}
+         \li Hosts: \b {Windows 10}
+    \row \li iOS 8, 9, 10 (armv7, arm64)
+         \li \b {Clang as provided by Apple}
+         \li \b {\macos 10.12 host}
+    \row \li Android (API Level: 16)
+         \li \b {GCC as provided by Google}, \b {MinGW 5.3}
+         \li Hosts: \b {RHEL 7.2 (64-bit)}, \b{\macos 10.12}, \b {Windows 7 (64-bit)}
+    \endtable
+
+//! [5.9] //! [latest]
+
 \section1 Qt 5.8
 
-//! [5.8] //! [latest]
-    \b {Supported until one year after release}
+//! [5.8]
+    \b {Supported until Jan 23, 2018}
 
     \table 80%
     \header \li Platform \li Compiler \li Notes
@@ -117,7 +193,7 @@ Mobile Platforms: \l {Qt for Android}{Android},
          \li Hosts: \b {Ubuntu 14.04 (64-bit)}, \macos, Windows
     \endtable
 
-//! [5.8] //! [latest]
+//! [5.8]
 
     \section1 Qt 5.7