Add CMake build files

src/sound/CMakeLists.txt

@@ -0,0 +1,30 @@
+add_library(snd OBJECT sound.c openal.c snd_opl.c snd_opl_nuked.c snd_resid.cc
+	midi.c midi_system.c snd_speaker.c snd_pssj.c snd_lpt_dac.c
+	snd_lpt_dss.c snd_adlib.c snd_adlibgold.c snd_ad1848.c snd_audiopci.c
+	snd_azt2316a.c snd_cms.c snd_gus.c snd_sb.c snd_sb_dsp.c snd_emu8k.c
+	snd_mpu401.c snd_sn76489.c snd_ssi2001.c snd_wss.c snd_ym7128.c)
+
+if(FLUIDSYNTH)
+	target_compile_definitions(snd PRIVATE USE_FLUIDSYNTH)
+	target_sources(snd PRIVATE midi_fluidsynth.c)
+endif()
+
+if(MUNT)
+	target_compile_definitions(snd PRIVATE USE_MUNT)
+	target_sources(snd PRIVATE midi_mt32.c)
+
+	add_subdirectory(munt)
+	target_link_libraries(86Box mt32emu)
+endif()
+
+if(PAS16)
+	target_compile_definitions(snd PRIVATE USE_PAS16)
+	target_sources(snd PRIVATE snd_pas16.c)
+endif()
+
+if(GUSMAX)
+	target_compile_definitions(snd PRIVATE USE_GUSMAX)
+endif()
+
+add_subdirectory(resid-fp)
+target_link_libraries(86Box resid-fp)