Fixed missing audio entries in configure summary.

configure.in

@@ -3161,16 +3161,19 @@ case "$host" in
             sysv5|solaris|hpux)
                 AC_DEFINE(SDL_AUDIO_DRIVER_SUNAUDIO, 1, [ ])
                 SOURCES="$SOURCES $srcdir/src/audio/sun/*.c"
+                SUMMARY_audio="${SUMMARY_audio} sun"
                 have_audio=yes
             ;;
             netbsd)  # Don't use this on OpenBSD, it's busted.
                 AC_DEFINE(SDL_AUDIO_DRIVER_NETBSD, 1, [ ])
                 SOURCES="$SOURCES $srcdir/src/audio/netbsd/*.c"
+                SUMMARY_audio="${SUMMARY_audio} netbsd"
                 have_audio=yes
             ;;
             aix)
                 AC_DEFINE(SDL_AUDIO_DRIVER_PAUDIO, 1, [ ])
                 SOURCES="$SOURCES $srcdir/src/audio/paudio/*.c"
+                SUMMARY_audio="${SUMMARY_audio} paudio"
                 have_audio=yes
             ;;
             android)
@@ -3410,6 +3413,7 @@ AC_HELP_STRING([--enable-render-d3d], [enable the Direct3D render driver [[defau
         if test x$enable_audio = xyes; then
             AC_DEFINE(SDL_AUDIO_DRIVER_HAIKU, 1, [ ])
             SOURCES="$SOURCES $srcdir/src/audio/haiku/*.cc"
+            SUMMARY_audio="${SUMMARY_audio} haiku"
             have_audio=yes
         fi
         # Set up files for the joystick library