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/*!
    \page configure-options.html
    \title Qt Configure Options
    \brief Configuring Qt's compile options

    \c configure is a command-line tool which determines how to build Qt for a
    particular platform. Configure can exclude a feature in Qt as well
    as determine how Qt builds and deploys applications onto host platforms.
    This page discusses some of the configure options, but for
    the full list of options, enter the command \c{configure -h}. Configure
    is located in \e qtbase but is also available from the main Qt source
    directory.

    Unless stated otherwise, the commands in this page are for the Linux
    platforms. On OS X and on Windows, the \c PATH and directory structure
    are different, therefore the commands will vary. Also, on Windows systems,
    the configure script is called \e configure.bat.

    After running \c configure, build the sources with the \c make tool
    belonging to the chosen toolchain.

    \section1 Source, Build, and Install Directories

    With configure, it is possible to configure Qt to install to a different
    directory than the source directory or the build directory. The \e source
    directory contains the source code and it is obtained from the source
    package. The \e build directory is where the build related files such as
    Makefiles, object files, and other intermediate files are stored. The \e
    install directory is where the binaries and libraries are installed, for use
    either by the system or by the application.

    It is often convenient to use a \e{shadow build}, when the build directory
    is not the same as the source directory. This method allows the source
    directory to be free from intermediate or generated files, and allows for
    multiple simultaneous builds with different configurations. To shadow-build,
    run \c configure from a separate directory:

   \code
    mkdir ~/qt-build
    cd ~/qt-build
    ~/qt-source/configure
    \endcode

    The Makefiles are at \e ~/qt-build and not in the source directory.

    After building, it may be necessary to install the libraries and binaries
    into the install directory. The default for the installation directory
    depends on the platform; \c configure's output mentions it. To modify the
    installation directory, use the \c -prefix option:

    \code
    ./configure -prefix /opt/Qt-5.1
    \endcode

    The installation directory serves as the parent directory of the \e bin, \e
    lib, and other installed Qt subdirectories.

    It is possible to set the install directory to the same directory as the
    build directory (this is termed a \e non-prefix build). In this case, Qt can
    be used straight out of the build directory, and \e must \e not be
    installed. This is the default under Windows, and when Qt is configured with
    the \c -developer-build option.

    \note When you are explicitly requesting a non-prefix configuration for a
    top-level build of Qt (all modules at once), set the prefix to
    \c{$builddir/qtbase}, not \c{$builddir}.

    \section1 Including and Excluding Qt Modules

    With configure, it is possible to include or exclude particular
    \l{All Modules}{Qt modules} in a Qt build. However, keep in mind that
    many modules depend on other modules, therefore, dependency issues
    can arise with some build configurations.

    \section2 Excluding a Qt Submodule

    Configure's \c -skip option allows certain Qt submodules to be excluded from
    the Qt build. These submodules correspond to the Git submodules in the
    standard Qt 5 repository. Note that many packages contain multiple Qt
    modules. For example, to exclude Qt NFC and Qt Bluetooth from the Qt build,
    provide \c{-skip qtconnectivity} as the argument to configure.

    \code
    ./configure -skip qtconnectivity
    \endcode

    \section2 Including or Excluding Features

    The \c{-feature-}\e{<feature>} and \c{-no-feature-}\e{<feature>} options
    include and exclude specific features, respectively, where \e{<feature>}
    is listed in the file \e{qtbase/src/corelib/global/qfeatures.txt}.

    For example, to disable \l Accessibility, provide \c -no-feature-accessibility
    as the argument:
    \code
    ./configure -no-feature-accessibility
    \endcode

    \note Features outside of \e qtbase are not included in the features list.

    \section1 Third-Party Libraries

    The Qt source packages include third-party libraries. To set whether Qt
    should use the system's versions of the libraries or to use the bundled
    version, pass either \c -system or \c -qt before the name of the library to
    configure.

    The table below summarizes the third-party options:
    \table
    \header
        \li Library Name
        \li Bundled in Qt
        \li Installed in System
    \row
        \li zlib
        \li \c -qt-zlib
        \li \c -system-zlib
    \row
        \li libjpeg
        \li \c -qt-libjpeg
        \li \c -system-libjpeg
    \row
        \li libpng
        \li \c -qt-libpng
        \li \c -system-libpng
    \row
        \li xcb
        \li \c -qt-xcb
        \li \c -system-xcb
    \row
        \li xkbcommon
        \li \c -qt-xkbcommon
        \li \c -system-xkbcommon
    \row
        \li freetype
        \li \c -qt-freetype
        \li \c -system-freetype
    \row
        \li PCRE
        \li \c -qt-pcre
        \li \c -system-pcre
    \row
        \li HarfBuzz-NG (experimental)
        \li \c -qt-harfbuzz
        \li \c -system-harfbuzz
    \endtable

    It is also possible to disable support for these libraries by using
    \c -no instead of \c{-qt}. For example, to use the system's xcb library
    and disable zlib support, enter the following:

    \code
    ./configure -no-zlib -qt-libjpeg -qt-libpng -system-xcb
    \endcode

    For a full list of options, consult the help with \c {configure -help}.

    \section1 Compiler Options

    The \c -platform option sets the host platform and the compiler for building
    the Qt sources. The list of supported platforms and compilers is found in
    the \l{Community Supported Platforms}{supported platforms} page while the
    full list is available in \e{qtbase/mkspecs} directory.

    For example, on Ubuntu Linux systems, Qt can be compiled by several
    compilers such as clang or g++:

    \code
    ./configure -platform linux-clang
    ./configure -platform linux-g++
    ./configure -platform linux-g++-32
    \endcode

    For \l{Qt for Windows}{Windows} machines, either MinGW or Visual Studio
    toolchains can be used to compile Qt.

    \code
    configure.bat -platform win32-g++
    configure.bat -platform win32-msvc2010
    \endcode

    Afterwards, the generated Makefiles will use the appropriate compiler
    commands.

    \section1 Cross-Compilation Options

    To configure Qt for cross-platform development and deployment, the
    development toolchain for the target platform needs to be set up. This
    set up varies among the \l{Supported Platforms}.

    Common options are:
    \list
    \li \c -xplatform - the target platform. Valid xplatform options are the same
    as the \c -platform options which are found in \e{qtbase/mkspecs}.
    \li \c -device - a specific device or chipsets. The list of devices that configure is compatible with are
    found in \e{qtbase/mkspecs/devices}. For more information, visit the \l{http://wiki.qt.io/Category:Devices}{Devices}
    Wiki page.
    \li \c -device-option - sets additional qmake variables. For example, \c{-device-option CROSS_COMPILE=}\e{<path-to-toolchain>} provides
    the environment variable, \c{CROSS_COMPILE}, as needed by certain devices.
    \endlist

    \note Toolchains for non-desktop targets often come with a so-called \e
    sysroot which Qt needs to be configured against.

    \section2 Specific Options for Platforms

    The following pages provide guidelines on how to configure Qt for specific
    platform development:
    \list
    \li \l{Building Qt 5 for Android} Wiki page
    \li \l{Qt for iOS - Building from Source}
    \li \l{Qt for WinRT#Building from source}{Qt for WinRT - Building from Source}
    \li \l{Qt for Embedded Linux#Configuring for a Specific Device}{Qt for Embedded Linux - Building from Source}
    \li \l{http://wiki.qt.io/Qt_RaspberryPi}{Qt for Raspberry Pi} - a community-driven site for
    Raspberry devices
    \li \l{http://wiki.qt.io/Category:Devices}{Devices} - a list of other devices and chipsets
    \endlist

    \section1 OpenGL Options for Windows

    On Windows, Qt can be configured with the system OpenGL or with \l{ANGLE}.
    By default, Qt is configured to use ANGLE, which is bundled with Qt and
    depends on the DirectX SDK. ANGLE enables running Qt applications that
    depend on OpenGL, without installing the latest OpenGL libraries.

    The \c -opengl option can be used to configure Qt to use
    the OpenGL in the target system, a different version of OpenGL ES (with or
    without ANGLE), or dynamically switch between the available OpenGL
    implementations.

    \code
    configure.bat -opengl desktop
    \endcode

    With the \c desktop option, Qt uses the OpenGL installed on Windows,
    requiring that the OpenGL in the target Windows machine is compatible with
    the application. The \c -opengl option accepts two versions of OpenGL ES, \c
    es2 for OpenGL ES 2.0 or \c es1 for OpenGL ES Common Profile.

    \code
    configure.bat -opengl es2
    \endcode

    You can also use \c{-opengl dynamic}, which enable applications to
    dynamically switch between the available options at runtime. For more
    details about the benefits of using dynamic GL-switching, see
    \l{Graphics Drivers}.
*/
