[fusl] Don't syscall(SYS_ioctl, ...) in stdio

fusl/src/stdio/__fdopen.c

 #include "stdio_impl.h"
 #include <stdlib.h>
-#include <sys/ioctl.h>
 #include <fcntl.h>
 #include <errno.h>
 #include <string.h>
+#include <unistd.h>
 
 FILE* __fdopen(int fd, const char* mode) {
   FILE* f;
-  struct winsize wsz;
 
   /* Check for valid initial mode character */
   if (!strchr("rwa", *mode)) {
     errno = EINVAL;
     return 0;
   }
 
   /* Allocate FILE+buffer or fail */
   if (!(f = malloc(sizeof *f + UNGET + BUFSIZ)))
     return 0;
@@ skipping 16 matching lines @@
       __syscall(SYS_fcntl, fd, F_SETFL, flags | O_APPEND);
     f->flags |= F_APP;
   }
 
   f->fd = fd;
   f->buf = (unsigned char*)f + sizeof *f + UNGET;
   f->buf_size = BUFSIZ;
 
   /* Activate line buffered mode for terminals */
   f->lbf = EOF;
-  if (!(f->flags & F_NOWR) && !__syscall(SYS_ioctl, fd, TIOCGWINSZ, &wsz))
+  if (!(f->flags & F_NOWR) && isatty(fd))
     f->lbf = '\n';
 
   /* Initialize op ptrs. No problem if some are unneeded. */
   f->read = __stdio_read;
   f->write = __stdio_write;
   f->seek = __stdio_seek;
   f->close = __stdio_close;
 
   if (!libc.threaded)
     f->lock = -1;
 
   /* Add new FILE to open file list */
   return __ofl_add(f);
 }
 
 weak_alias(__fdopen, fdopen);