These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 1.81 s (backtrack: 0/20).

[ebuild  N     ] media-libs/libogg-1.3.6::gentoo  USE="-static-libs" 430 KiB
[ebuild  N     ] media-sound/fluid-soundfont-3.1::gentoo  USE="-timidity" 131676 KiB
[ebuild  N     ] media-libs/alsa-topology-conf-1.2.5.1-r1::gentoo  USE="-verify-sig" 12 KiB
[ebuild  N     ] media-libs/alsa-ucm-conf-1.2.16.1::gentoo  USE="-verify-sig" 83 KiB
[ebuild  N     ] x11-libs/libXcursor-1.2.3::gentoo  USE="-doc" 286 KiB
[ebuild  N     ] media-libs/flac-1.5.0:0/11-14::gentoo  USE="cxx -debug -ogg -static-libs" CPU_FLAGS_X86="avx avx2" 1054 KiB
[ebuild  N     ] media-libs/alsa-lib-1.2.16.1::gentoo  USE="python -debug -doc -verify-sig" PYTHON_SINGLE_TARGET="python3_14 -python3_12 -python3_13 (-python3_15)" 1104 KiB
[ebuild  N     ] media-libs/libvorbis-1.3.7-r2::gentoo  USE="-static-libs -test" 1176 KiB
[ebuild  N     ] dev-libs/libxdg-basedir-1.2.3-r1::gentoo  USE="-doc" 31 KiB
[ebuild  N     ] dev-games/ode-0.14-r1:0/6::gentoo  USE="-debug -doc -double-precision -examples -gyroscopic -static-libs" 3924 KiB
[ebuild  N     ] media-libs/libmodplug-0.8.9.1::gentoo  234 KiB
[ebuild  N     ] media-sound/lame-3.100-r3::gentoo  USE="frontend -debug -mp3rtp -sndfile -static-libs" CPU_FLAGS_X86="(-mmx)" 1489 KiB
[ebuild  NS    ] dev-lang/lua-5.1.5-r200:5.1::gentoo [5.4.8:5.4::gentoo] USE="deprecated readline" 389 KiB
[ebuild  N     ] app-eselect/eselect-mpg123-0.1-r1::gentoo  0 KiB
[ebuild  N     ] media-sound/mpg123-base-1.33.7::gentoo  USE="alsa ipv6 (-coreaudio) -int-quality -jack -nas -oss -portaudio -pulseaudio -sdl -verify-sig" CPU_FLAGS_X86="sse (-3dnow) (-3dnowext) (-mmx)" 1100 KiB
[ebuild  N     ] media-libs/opus-1.6.1::gentoo  USE="-custom-modes -debug -deep-plc -doc -dred -hardened -osce -static-libs -test" CPU_FLAGS_X86="sse" 10228 KiB
[ebuild  N     ] media-libs/libsndfile-1.2.2-r2::gentoo  USE="alsa sqlite -minimal -test" 714 KiB
[ebuild  N     ] media-libs/libsdl2-2.32.10::gentoo  USE="X alsa dbus haptic joystick opengl sound video (-aqua) (-custom-cflags) -doc -fcitx -gles1 -gles2 -ibus -jack -kms -libsamplerate -nas -oss -pipewire -pulseaudio -sndio -static-libs -test -udev -vulkan -wayland -xscreensaver" CPU_FLAGS_X86="mmx sse sse2 sse3 -3dnow" 7452 KiB
[ebuild  N     ] media-sound/fluidsynth-2.5.7-r1:0/3::gentoo  USE="alsa dbus ipv6 openmp readline sndfile threads -debug -doc -jack -ladspa -oss -pipewire -portaudio -pulseaudio -sdl (-systemd)" 2124 KiB
[ebuild  N     ] media-libs/sdl2-mixer-2.8.2-r1::gentoo  USE="fluidsynth midi mod modplug mp3 vorbis wav -flac -gme -opus -playtools -stb -timidity -tremor -wavpack -xmp" 5861 KiB
[ebuild  N     ] media-libs/sdl2-net-2.2.0::gentoo  USE="-static-libs" 8504 KiB
[ebuild  N     ] media-libs/sdl2-ttf-2.24.0::gentoo  USE="X harfbuzz -static-libs" 13024 KiB
[ebuild  N     ] games-sports/xmoto-0.6.3::gentoo  USE="nls system-ode -double-precision" LUA_SINGLE_TARGET="lua5-1 -lua5-3 -lua5-4" 41127 KiB

Total: 23 packages (22 new, 1 in new slot), Size of downloads: 232011 KiB

The following USE changes are necessary to proceed:
 (see "package.use" in the portage(5) man page for more details)
# required by games-sports/xmoto-0.6.3::gentoo
# required by =games-sports/xmoto-0.6.3 (argument)
>=media-libs/sdl2-mixer-2.8.2-r1 vorbis