sdl3-mixer: add SDL3_mixer 3.2.4

SDL3-native audio mixer library (libSDL3_mixer), built directly against
SDL3 so it coexists with sdl2-mixer's libSDL2_mixer. MIDI, Opus, WavPack
and MOD support via libfluidsynth, libopusfile, libwavpack and libxmp.

https://github.com/libsdl-org/SDL_mixer/releases/tag/release-3.2.4
Signed-off-by: Daniel Golle <daniel@makrotopia.org>

libs/sdl3-mixer/Makefile

@@ -0,0 +1,50 @@
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=sdl3-mixer
+PKG_VERSION:=3.2.4
+PKG_RELEASE:=1
+
+PKG_SOURCE:=SDL3_mixer-$(PKG_VERSION).tar.gz
+PKG_SOURCE_URL:=https://codeload.github.com/libsdl-org/SDL_mixer/tar.gz/release-$(PKG_VERSION)?
+PKG_HASH:=f2ea848ccdf2f394cd4973ee0f6c482e04511044695cccfd46bab6dcd7f780aa
+
+PKG_BUILD_DIR:=$(BUILD_DIR)/SDL_mixer-release-$(PKG_VERSION)
+
+PKG_MAINTAINER:=Daniel Golle <daniel@makrotopia.org>
+PKG_LICENSE:=BSD-3c
+PKG_LICENSE_FILES:=LICENSE.txt
+
+CMAKE_INSTALL:=1
+
+include $(INCLUDE_DIR)/package.mk
+include $(INCLUDE_DIR)/cmake.mk
+
+CMAKE_BINARY_SUBDIR:=openwrt-build
+
+CMAKE_OPTIONS += \
+	-DSDLMIXER_SAMPLES=OFF \
+	-DSDLMIXER_VENDORED=OFF \
+	-DSDLMIXER_MIDI_FLUIDSYNTH_SHARED=ON
+
+define Build/InstallDev
+	$(call Build/InstallDev/cmake,$(1))
+endef
+
+define Package/libsdl3-mixer
+  SECTION:=libs
+  CATEGORY:=Libraries
+  TITLE:=SDL3 Mixer
+  URL:=https://www.libsdl.org/
+  DEPENDS:=+libsdl3 +libfluidsynth +libopusfile +libwavpack +libxmp
+endef
+
+define Package/libsdl3-mixer/description
+  SDL3 Audio Mixer library
+endef
+
+define Package/libsdl3-mixer/install
+	$(INSTALL_DIR) $(1)/usr/lib
+	$(CP) $(PKG_INSTALL_DIR)/usr/lib/libSDL3_mixer*.so* $(1)/usr/lib/
+endef
+
+$(eval $(call BuildPackage,libsdl3-mixer))