let filename = find_on_include_path filename in
if optflag && not (Sys.file_exists filename) then env
else (
let fp = open_in filename in
let lexbuf = Lexing.from_channel fp in
lexbuf.lex_curr_p <- { lexbuf.lex_curr_p with pos_fname = filename };
let filename = find_on_include_path filename in
if optflag && not (Sys.file_exists filename) then env
else (
let fp = open_in filename in
let lexbuf = Lexing.from_channel fp in
lexbuf.lex_curr_p <- { lexbuf.lex_curr_p with pos_fname = filename };