Warning when extra-output is requested w/o filename (#8671)

Co-authored-by: Alex Reinking <[email protected]>

Author: FabianSchuetze

cmake/HalideGeneratorHelpers.cmake

@@ -493,6 +493,14 @@ function(add_halide_library TARGET)
         message(AUTHOR_WARNING "Arguments to add_halide_library were not recognized: ${ARG_UNPARSED_ARGUMENTS}")
     endif ()
 
+    set(nonEmptyArgs ${oneValueArgs})
+    list(REMOVE_ITEM nonEmptyArgs AUTOSCHEDULER FUNCTION_NAME GENERATOR NAMESPACE USE_RUNTIME)
+    foreach (name IN LISTS ARG_KEYWORDS_MISSING_VALUES)
+        if (name IN_LIST nonEmptyArgs)
+            message(AUTHOR_WARNING "The argument ${name} passed to add_halide_library is undefined")
+        endif ()
+    endforeach ()
+
     if (ARG_C_BACKEND AND ARG_TARGETS)
         message(AUTHOR_WARNING "The C backend sources will be compiled with the current CMake toolchain.")
     endif ()