cmake: move include(sdlfind.cmake) to main cmake script

cmake/sdlchecks.cmake

@@ -1,6 +1,3 @@
-include(CMakeParseArguments)
-include(${SDL3_SOURCE_DIR}/cmake/sdlfind.cmake)
-
 macro(FindLibraryAndSONAME _LIB)
   cmake_parse_arguments(FLAS "" "" "LIBDIRS" ${ARGN})
 

cmake/sdlfind.cmake

@@ -6,4 +6,4 @@ macro(sdlFindALSA)
     set_property(TARGET ALSA::ALSA PROPERTY INTERFACE_INCLUDE_DIRECTORIES ${ALSA_INCLUDE_DIRS})
     set_property(TARGET ALSA::ALSA APPEND PROPERTY IMPORTED_LOCATION ${ALSA_LIBRARY})
   endif()
-endmacro()
+endmacro()