In file included from /usr/include/readline/readline.h:35,
                 from main.c:2:
/usr/include/readline/rltypedefs.h:71:28: error: unknown type name ‘FILE’
   71 | typedef int rl_getc_func_t PARAMS((FILE *));
      |                            ^~~~~~
In file included from /usr/include/readline/readline.h:36,
                 from main.c:2:
/usr/include/readline/rltypedefs.h:1:1: note: ‘FILE’ is defined in header ‘<stdio.h>’; did you forget to ‘#include <stdio.h>’?
  +++ |+#include <stdio.h>
    1 | /* rltypedefs.h -- Type declarations for readline functions. */
In file included from /usr/include/readline/readline.h:35,
                 from main.c:2:
/usr/include/readline/readline.h:438:20: error: unknown type name ‘FILE’
  438 | extern int rl_getc PARAMS((FILE *));
      |                    ^~~~~~
In file included from main.c:2:
/usr/include/readline/readline.h:39:1: note: ‘FILE’ is defined in header ‘<stdio.h>’; did you forget to ‘#include <stdio.h>’?
   38 | #  include <readline/tilde.h>
  +++ |+#include <stdio.h>
   39 | #endif
/usr/include/readline/readline.h:568:8: error: unknown type name ‘FILE’
  568 | extern FILE *rl_instream;
      |        ^~~~
/usr/include/readline/readline.h:569:8: error: unknown type name ‘FILE’
  569 | extern FILE *rl_outstream;
      |        ^~~~
/usr/include/readline/readline.h:598:8: error: unknown type name ‘rl_getc_func_t’
  598 | extern rl_getc_func_t *rl_getc_function;
      |        ^~~~~~~~~~~~~~
/usr/include/readline/readline.h:927:3: error: unknown type name ‘FILE’
  927 |   FILE *inf;
      |   ^~~~
/usr/include/readline/readline.h:928:3: error: unknown type name ‘FILE’
  928 |   FILE *outf;
      |   ^~~~
make: *** [Makefile:5: main.o] Error 1