Fix STD build failing for target_os = espidf

Author: ivmarkov

library/std/src/sys/fs/mod.rs

@@ -117,9 +117,16 @@ pub fn set_permissions(path: &Path, perm: FilePermissions) -> io::Result<()> {
 #[cfg(unix)]
 pub fn set_permissions_nofollow(path: &Path, perm: crate::fs::Permissions) -> io::Result<()> {
     use crate::fs::OpenOptions;
-    use crate::os::unix::fs::OpenOptionsExt;
 
-    OpenOptions::new().custom_flags(libc::O_NOFOLLOW).open(path)?.set_permissions(perm)
+    let mut options = OpenOptions::new();
+
+    #[cfg(not(target_os = "espidf"))]
+    {
+        use crate::os::unix::fs::OpenOptionsExt;
+        options.custom_flags(libc::O_NOFOLLOW);
+    }
+
+    options.open(path)?.set_permissions(perm)
 }
 
 #[cfg(not(unix))]