Wipe working directory before building Atmel Studio extension.

LUFA/StudioIntegration/makefile

@@ -45,7 +45,10 @@ MSHELP_GEN_PARAMS   := --stringparam generate.toc "book toc"                \
                        --stringparam root.filename "LUFA"                   \
                        --stringparam html.stylesheet "lufa_studio_help_styling.css"
 
-all: generate_xml check_filenames generate_vsix
+all: clear_project_dirs generate_xml check_filenames generate_vsix
+
+clear_project_dirs:
+	@make -s -C $(LUFA_ROOT)/.. clean
 
 clean:
 	@rm -f $(TEMP_MANIFEST_XML) $(MODULE_OUTPUT_XML) $(EXTENSION_OUTPUT_XML) $(DOXYGEN_TAG_FILE_XML) $(DOXYGEN_COMBINED_XML) $(MSHELP_OUTPUT_XML)