tree-wide: use -EBADF more

src/basic/fd-util.h

@@ -22,8 +22,8 @@ int safe_close(int fd);
 void safe_close_pair(int p[static 2]);
 
 static inline int safe_close_above_stdio(int fd) {
-        if (fd < 3) /* Don't close stdin/stdout/stderr, but still invalidate the fd by returning -1 */
-                return -1;
+        if (fd < 3) /* Don't close stdin/stdout/stderr, but still invalidate the fd by returning -EBADF. */
+                return -EBADF;
 
         return safe_close(fd);
 }
@@ -87,7 +87,7 @@ int fd_move_above_stdio(int fd);
 int rearrange_stdio(int original_input_fd, int original_output_fd, int original_error_fd);
 
 static inline int make_null_stdio(void) {
-        return rearrange_stdio(-1, -1, -1);
+        return rearrange_stdio(-EBADF, -EBADF, -EBADF);
 }
 
 /* Like TAKE_PTR() but for file descriptors, resetting them to -1 */