syntax_data: {"ast_node_type":"other","tokens":[{"end":36,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:     // known to be possibly-harmful.
context_before:     // using. Unless requested otherwise, clean CFLAGS of options that are
context_after:     let no_clean = env::var_os(&*ENV_NO_CLEAN_CFLAGS).is_some();