AC_TRY_COMPILE([
         #include <linux/fb.h>
         #include <linux/kd.h>
         #include <linux/keyboard.h>
        ],[
        ],[
        video_fbcon=yes
        ])
        AC_MSG_RESULT($video_fbcon)
        if test x$video_fbcon = xyes; then
            CFLAGS="$CFLAGS -DENABLE_FBCON"
            VIDEO_SUBDIRS="$VIDEO_SUBDIRS fbcon"
            VIDEO_DRIVERS="$VIDEO_DRIVERS fbcon/libvideo_fbcon.la"
        fi
    fi
}

dnl Find DirectFB
CheckDirectFB()
{
    AC_ARG_ENABLE(video-directfb,
[  --enable-video-directfb    use DirectFB video driver [default=yes]],
                  , enable_video_directfb=yes)
    if test x$enable_video = xyes -a x$enable_video_directfb = xyes; then
        video_directfb=no

        AC_PATH_PROG(PKG_CONFIG, pkg-config, no)
        if test x$PKG_CONFIG = xno ; then
            AC_MSG_WARN([*** pkg-config is required to build the DirectFB video driver.])
        else
            AC_MSG_CHECKING(for DirectFB support)

            if ! $PKG_CONFIG --atleast-pkgconfig-version 0.5 ; then
                AC_MSG_ERROR([*** pkg-config too old; version 0.5 or better required.])
            fi

            DIRECTFB_REQUIRED_VERSION=0.9.9

            if $PKG_CONFIG --atleast-version $DIRECTFB_REQUIRED_VERSION directfb ; then
                DIRECTFB_CFLAGS=`$PKG_CONFIG --cflags directfb`
                DIRECTFB_LIBS=`$PKG_CONFIG --libs directfb`
                video_directfb=yes
            fi
        fi

        AC_MSG_RESULT($video_directfb)
        if test x$video_directfb = xyes; then
            CFLAGS="$CFLAGS -DENABLE_DIRECTFB"
            VIDEO_SUBDIRS="$VIDEO_SUBDIRS directfb"
            VIDEO_DRIVERS="$VIDEO_DRIVERS directfb/libvideo_directfb.la"

            AC_SUBST(DIRECTFB_CFLAGS)
            AC_SUBST(DIRECTFB_LIBS)
        fi
    fi
}

dnl See if we're running on PlayStation 2 hardware
CheckPS2GS()
{
    AC_ARG_ENABLE(video-ps2gs,
[  --enable-video-ps2gs    use PlayStation 2 GS video driver [default=yes]],
                  , enable_video_ps2gs=yes)
    if test x$enable_video = xyes -a x$enable_video_ps2gs = xyes; then
        AC_MSG_CHECKING(for PlayStation 2 GS support)
        video_ps2gs=no
        AC_TRY_COMPILE([
         #include <linux/ps2/dev.h>
         #include <linux/ps2/gs.h>
        ],[
        ],[
        video_ps2gs=yes
        ])
        AC_MSG_RESULT($video_ps2gs)
        if test x$video_ps2gs = xyes; then
            CFLAGS="$CFLAGS -DENABLE_PS2GS"
            VIDEO_SUBDIRS="$VIDEO_SUBDIRS ps2gs"
            VIDEO_DRIVERS="$VIDEO_DRIVERS ps2gs/libvideo_ps2gs.la"
        fi
    fi
}

dnl Find the GGI includes
CheckGGI()
{
    AC_ARG_ENABLE(video-ggi,
[  --enable-video-ggi      use GGI video driver [default=no]],
                  , enable_video_ggi=no)
    if test x$enable_video = xyes -a x$enable_video_ggi = xyes; then
        AC_MSG_CHECKING(for GGI support)
        video_ggi=no
        AC_TRY_COMPILE([
         #include <ggi/ggi.h>
         #include <ggi/gii.h>
        ],[
        ],[
        video_ggi=yes
        ])
        AC_MSG_RESULT($video_ggi)
        if test x$video_ggi = xyes; then
            CFLAGS="$CFLAGS $X_CFLAGS -DENABLE_GGI"
            SYSTEM_LIBS="$SYSTEM_LIBS -lggi -lgii -lgg"

            VIDEO_SUBDIRS="$VIDEO_SUBDIRS ggi"
            VIDEO_DRIVERS="$VIDEO_DRIVERS ggi/libvideo_ggi.la"
        fi
    fi
}

dnl Find the SVGAlib includes and libraries
CheckSVGA()
{
    AC_ARG_ENABLE(video-svga,
[  --enable-video-svga     use SVGAlib video driver [default=no]],
                  , enable_video_svga=no)
    if test x$enable_video = xyes -a x$enable_video_svga = xyes; then
        AC_MSG_CHECKING(for SVGAlib (1.4.0+) support)
        video_svga=no
        AC_TRY_COMPILE([
         #include <vga.h>
         #include <vgamouse.h>
         #include <vgakeyboard.h>
        ],[
         if ( SCANCODE_RIGHTWIN && SCANCODE_LEFTWIN ) {
             exit(0);
         }
        ],[
        video_svga=yes
        ])
        AC_MSG_RESULT($video_svga)
        if test x$video_svga = xyes; then
            CFLAGS="$CFLAGS -DENABLE_SVGALIB"
            SYSTEM_LIBS="$SYSTEM_LIBS -lvga"

            VIDEO_SUBDIRS="$VIDEO_SUBDIRS svga"
            VIDEO_DRIVERS="$VIDEO_DRIVERS svga/libvideo_svga.la"
        fi
    fi
}

dnl Find the VGL includes and libraries
CheckVGL()
{
    AC_ARG_ENABLE(video-vgl,
[  --enable-video-vgl     use VGL video driver [default=no]],
                  , enable_video_vgl=no)
    if test x$enable_video = xyes -a x$enable_video_vgl = xyes; then
        AC_MSG_CHECKING(for libVGL support)
        video_vgl=no
        AC_TRY_COMPILE([
         #include <sys/fbio.h>
         #include <sys/consio.h>
         #include <sys/kbio.h>
         #include <vgl.h>
        ],[
         VGLBitmap bitmap;
         exit(bitmap.Bitmap);
        ],[
        video_vgl=yes
        ])
        AC_MSG_RESULT($video_vgl)
        if test x$video_vgl = xyes; then
            CFLAGS="$CFLAGS -DENABLE_VGL"
            SYSTEM_LIBS="$SYSTEM_LIBS -lvgl"

            VIDEO_SUBDIRS="$VIDEO_SUBDIRS vgl"
            VIDEO_DRIVERS="$VIDEO_DRIVERS vgl/libvideo_vgl.la"
        fi
    fi
}

dnl Find the AAlib includes
CheckAAlib()
{
    AC_ARG_ENABLE(video-aalib,
[  --enable-video-aalib    use AAlib video driver [default=no]],
                  , enable_video_aalib=no)
    if test x$enable_video = xyes -a x$enable_video_aalib = xyes; then
        AC_MSG_CHECKING(for AAlib support)
        video_aalib=no
        AC_TRY_COMPILE([
         #include <aalib.h>
        ],[
        ],[
        video_aalib=yes
        ])
        AC_MSG_RESULT($video_aalib)
        if test x$video_aalib = xyes; then
            CFLAGS="$CFLAGS -DENABLE_AALIB"
            SYSTEM_LIBS="$SYSTEM_LIBS -laa"

            VIDEO_SUBDIRS="$VIDEO_SUBDIRS aalib"
            VIDEO_DRIVERS="$VIDEO_DRIVERS aalib/libvideo_aa.la"
        fi
    fi
}

dnl Set up the Atari Xbios driver
CheckAtariXbiosVideo()
{
    AC_ARG_ENABLE(xbios,
[  --enable-video-xbios    use Atari Xbios video driver [default=yes]],
                  , enable_video_xbios=yes)
    video_xbios=no
    if test x$enable_video = xyes -a x$enable_video_xbios = xyes; then
        video_xbios=yes
        CFLAGS="$CFLAGS -DENABLE_XBIOS"
        VIDEO_SUBDIRS="$VIDEO_SUBDIRS xbios"
        VIDEO_DRIVERS="$VIDEO_DRIVERS xbios/libvideo_xbios.la"
    fi
}

dnl Set up the Atari Gem driver
CheckAtariGemVideo()
{
    AC_ARG_ENABLE(gem,
[  --enable-video-gem      use Atari Gem video driver [default=yes]],
                  , enable_video_gem=yes)
    if test x$enable_video = xyes -a x$enable_video_gem = xyes; then
        video_gem=no
        AC_CHECK_HEADER(gem.h, have_gem_hdr=yes)
        AC_CHECK_LIB(gem, appl_init, have_gem_lib=yes)
        if test x$have_gem_hdr = xyes -a x$have_gem_lib = xyes; then
            video_gem=yes
            CFLAGS="$CFLAGS -DENABLE_GEM"
            SYSTEM_LIBS="$SYSTEM_LIBS -lgem"
            VIDEO_SUBDIRS="$VIDEO_SUBDIRS gem"
            VIDEO_DRIVERS="$VIDEO_DRIVERS gem/libvideo_gem.la"
        fi
    fi
}

dnl Set up the Atari Bios keyboard driver
CheckAtariBiosEvent()
{
    CFLAGS="$CFLAGS -I\$(top_srcdir)/src/video/ataricommon"
    VIDEO_SUBDIRS="$VIDEO_SUBDIRS ataricommon"
    VIDEO_DRIVERS="$VIDEO_DRIVERS ataricommon/libvideo_ataricommon.la"
}

dnl rcg04172001 Set up the Null video driver.
CheckDummyVideo()
{
    AC_ARG_ENABLE(video-dummy,
[  --enable-video-dummy    use dummy video driver [default=yes]],
                  , enable_video_dummy=yes)
    if test x$enable_video_dummy = xyes; then
      CFLAGS="$CFLAGS -DENABLE_DUMMYVIDEO"
      VIDEO_SUBDIRS="$VIDEO_SUBDIRS dummy"
      VIDEO_DRIVERS="$VIDEO_DRIVERS dummy/libvideo_null.la"
    fi
}

dnl Check to see if OpenGL support is desired
AC_ARG_ENABLE(video-opengl,
[  --enable-video-opengl   include OpenGL context creation [default=yes]],
              , enable_video_opengl=yes)

dnl Find OpenGL
CheckOpenGL()
{
    if test x$enable_video = xyes -a x$enable_video_opengl = xyes; then
        AC_MSG_CHECKING(for OpenGL (GLX) support)
        video_opengl=no
        AC_TRY_COMPILE([
         #include <GL/gl.h>
         #include <GL/glx.h>
         #include <dlfcn.h> /* For loading extensions */
        ],[
        ],[
        video_opengl=yes
        ])
        AC_MSG_RESULT($video_opengl)
        if test x$video_opengl = xyes; then
            CFLAGS="$CFLAGS -DHAVE_OPENGL"
            if test x$use_dlopen != xyes; then
                AC_CHECK_LIB(dl, dlopen, SYSTEM_LIBS="$SYSTEM_LIBS -ldl")
            fi
        fi
    fi
}

dnl Find QNX RtP OpenGL
CheckOpenGLQNX()
{
    if test x$enable_video = xyes -a x$enable_video_opengl = xyes; then
        AC_MSG_CHECKING(for OpenGL (Photon) support)
        video_opengl=no
        AC_TRY_COMPILE([
         #include <GL/gl.h>
        ],[
        ],[
        video_opengl=yes
        ])
        AC_MSG_RESULT($video_opengl)
        if test x$video_opengl = xyes; then
            CFLAGS="$CFLAGS -DHAVE_OPENGL"
            SYSTEM_LIBS="$SYSTEM_LIBS -lGL"
        fi
    fi
}

dnl Check for BeOS OpenGL
CheckBeGL()
{
    if test x$enable_video = xyes -a x$enable_video_opengl = xyes; then
        CFLAGS="$CFLAGS -DHAVE_OPENGL"
        SYSTEM_LIBS="$SYSTEM_LIBS -lGL"
    fi
}

dnl Check for MacOS OpenGL
CheckMacGL()
{
    if test x$enable_video = xyes -a x$enable_video_opengl = xyes; then
        CFLAGS="$CFLAGS -DHAVE_OPENGL"
        case "$target" in
            *-*-darwin*)
                SDL_LIBS="$SDL_LIBS -framework OpenGL -framework AGL"
        esac
    fi
}

dnl See if we can use the new unified event interface in Linux 2.4
CheckInputEvents()
{
    dnl Check for Linux 2.4 unified input event interface support
    AC_ARG_ENABLE(input-events,
[  --enable-input-events   use Linux 2.4 unified input interface [default=yes]],
                  , enable_input_events=yes)
    if test x$enable_input_events = xyes; then
        AC_MSG_CHECKING(for Linux 2.4 unified input interface)
        use_input_events=no
        AC_TRY_COMPILE([
          #include <linux/input.h>
        ],[
          #ifndef EVIOCGNAME
          #error EVIOCGNAME() ioctl not available
          #endif
        ],[
        use_input_events=yes
        ])
        AC_MSG_RESULT($use_input_events)
        if test x$use_input_events = xyes; then
            CFLAGS="$CFLAGS -DUSE_INPUT_EVENTS"
        fi
    fi
}

dnl See what type of thread model to use on Linux and Solaris
CheckPTHREAD()
{
    dnl Check for pthread support
    AC_ARG_ENABLE(pthreads,
[  --enable-pthreads       use POSIX threads for multi-threading [default=yes]],
                  , enable_pthreads=yes)
    dnl This is used on Linux for glibc binary compatibility (Doh!)
    AC_ARG_ENABLE(pthread-sem,
[  --enable-pthread-sem    use pthread semaphores [default=yes]],
                  , enable_pthread_sem=yes)
    ac_save_libs="$LIBS"
    case "$target" in
        *-*-bsdi*)
            pthread_cflags="-D_REENTRANT -D_THREAD_SAFE"
            pthread_lib=""
            ;;
        *-*-darwin*)
            pthread_cflags="-D_THREAD_SAFE"
# causes Carbon.p complaints?
#            pthread_cflags="-D_REENTRANT -D_THREAD_SAFE"