rebuild-testbench.sh: error when unknown arguments are passed

Silently discarding user input is really bad.

Signed-off-by: Marc Herbert <marc.herbert@intel.com>

scripts/rebuild-testbench.sh

@@ -136,7 +136,16 @@ main()
         esac
     done
 
+    # This automagically removes the -- sentinel itself if any.
+    shift "$((OPTIND -1))"
+    # Error on spurious arguments.
+    test $# -eq 0 || {
+        print_usage
+        die "Unknown arguments: %s\n" "$*"
+    }
+
     rebuild_testbench
+
     printf '\n'
     testbench_usage
 }

tools/testbench/CMakeLists.txt

@@ -50,6 +50,8 @@ install(TARGETS testbench DESTINATION bin)
 
 include(ExternalProject)
 
+# Should we do this? Only for sof_ep, not for parser_ep?
+# https://stackoverflow.com/questions/12021448/how-can-cmake-arguments-be-forwarded-to-externalproject
 ExternalProject_Add(sof_ep
 	DOWNLOAD_COMMAND ""
 	SOURCE_DIR "${sof_source_directory}"