cmake: Add xmp-lite

This is a very lightweight module playback engine which will replace
OpenMPT.

thirdparty/CMakeLists.txt

@@ -605,4 +605,64 @@ if(DiscordRPC_ADDED)
 	endif()
 endif()
 
+CPMAddPackage(
+	NAME xmp-lite
+	VERSION 4.5.0
+	URL "https://github.com/libxmp/libxmp/releases/download/libxmp-4.5.0/libxmp-lite-4.5.0.tar.gz"
+	EXCLUDE_FROM_ALL ON
+	DOWNLOAD_ONLY ON
+)
+if(xmp-lite_ADDED)
+	set(xmp_sources
+		virtual.c
+		format.c
+		period.c
+		player.c
+		read_event.c
+		misc.c
+		dataio.c
+		lfo.c
+		scan.c
+		control.c
+		filter.c
+		effects.c
+		mixer.c
+		mix_all.c
+		load_helpers.c
+		load.c
+		hio.c
+		smix.c
+		memio.c
+		win32.c
+
+		loaders/common.c
+		loaders/itsex.c
+		loaders/sample.c
+		loaders/xm_load.c
+		loaders/mod_load.c
+		loaders/s3m_load.c
+		loaders/it_load.c
+	)
+	list(TRANSFORM xmp_sources PREPEND "${xmp-lite_SOURCE_DIR}/src/")
+
+	add_library(xmp-lite "${SRB2_INTERNAL_LIBRARY_TYPE}" ${xmp_sources})
+
+	target_compile_definitions(xmp-lite PRIVATE -D_REENTRANT -DLIBXMP_CORE_PLAYER -DLIBXMP_NO_PROWIZARD -DLIBXMP_NO_DEPACKERS)
+	if("${SRB2_INTERNAL_LIBRARY_TYPE}" STREQUAL "STATIC")
+		if(WIN32)
+			# BUILDING_STATIC has to be public to work around a bug in xmp.h
+			# which adds __declspec(dllimport) even when statically linking
+			target_compile_definitions(xmp-lite PUBLIC -DBUILDING_STATIC)
+		else()
+			target_compile_definitions(xmp-lite PRIVATE -DBUILDING_STATIC)
+		endif()
+	else()
+		target_compile_definitions(xmp-lite PRIVATE -DBUILDING_DLL)
+	endif()
+	target_include_directories(xmp-lite PRIVATE "${xmp-lite_SOURCE_DIR}/src")
+	target_include_directories(xmp-lite PUBLIC "${xmp-lite_SOURCE_DIR}/include/libxmp-lite")
+
+	add_library(xmp-lite::xmp-lite ALIAS xmp-lite)
+endif()
+
 add_subdirectory(tcbrindle_span)