[Piglit] [NOTICE] Piglit's build requirements for Linux will soon change

[Chad Versace]

Just an early alert so your Piglit build doesn't break unexpectedly. Requirements for non-Linux systems will not change.

On Linux, Piglit will soon require Waffle as a build requirement by default. If you wish to continue building Piglit without Waffle, then configure Piglit with `cmake -DPIGLIT_USE_WAFFLE=0 $your_usual_flags`. Otherwise, you need to install Waffle. I suggest you install from the 1.0 release branch.

To install Waffle from source:
    git clone -b 1.0 git://people.freedesktop.org/~chadversary/waffle.git /tmp/waffle
    cd /tmp/waffle
    cmake . \
        -DCMAKE_BUILD_TYPE=Debug  \           # Or Release, your choice.
        -DCMAKE_INSTALL_PREFIX=/usr/local \   # Or wherever Piglit will find it.
        -Dwaffle_has_glx=1 \                  # For GLX support.
        -Dwaffle_has_x11_egl=1 \              # For X11/EGL support.
        -Dwaffle_has_wayland=1 \              # For Wayland support.
    make
    sudo make install

For each of the platform flags above (GLX, X/EGL, Wayland), you can omit that flag if you don't want support for that platform.

For more information about Waffle, see http://people.freedesktop.org/~chadversary/waffle.

-Chad