cmake: use CONFIGURE_DEPENDS flag in GLOBs

cmake/sdlcommands.cmake

@@ -19,9 +19,15 @@ endfunction()
 # Use sdl_glob_sources to add glob sources to SDL3-shared, to SDL3-static, or to both.
 function(sdl_glob_sources)
   cmake_parse_arguments(ARGS "" "" "SHARED;STATIC" ${ARGN})
-  file(GLOB shared_sources ${ARGS_SHARED})
-  file(GLOB static_sources ${ARGS_STATIC})
-  file(GLOB both_sources ${ARGS_UNPARSED_ARGUMENTS})
+  if(ARGS_SHARED)
+    file(GLOB shared_sources CONFIGURE_DEPENDS ${ARGS_SHARED})
+  endif()
+  if(ARGS_STATIC)
+    file(GLOB static_sources CONFIGURE_DEPENDS ${ARGS_STATIC})
+  endif()
+  if(ARGS_UNPARSED_ARGUMENTS)
+    file(GLOB both_sources CONFIGURE_DEPENDS ${ARGS_UNPARSED_ARGUMENTS})
+  endif()
   if(TARGET SDL3-shared)
     target_sources(SDL3-shared PRIVATE ${shared_sources} ${both_sources})
   endif()