Add another deprecated attribute for something removed in main

Removed in <#3526>.

src/fuchsia/mod.rs

@@ -3787,6 +3787,7 @@ extern "C" {
     pub fn close(fd: ::c_int) -> ::c_int;
     pub fn dup(fd: ::c_int) -> ::c_int;
     pub fn dup2(src: ::c_int, dst: ::c_int) -> ::c_int;
+
     pub fn execl(path: *const c_char, arg0: *const c_char, ...) -> ::c_int;
     pub fn execle(path: *const ::c_char, arg0: *const ::c_char, ...) -> ::c_int;
     pub fn execlp(file: *const ::c_char, arg0: *const ::c_char, ...) -> ::c_int;

src/unix/bsd/apple/mod.rs

@@ -6807,6 +6807,7 @@ cfg_if! {
 // These require a dependency on `libiconv`, and including this when built as
 // part of `std` means every Rust program gets it. Ideally we would have a link
 // modifier to only include these if they are used, but we do not.
+#[deprecated(note = "Will be removed in 1.0 to avoid the `iconv` dependency")]
 #[cfg_attr(not(feature = "rustc-dep-of-std"), link(name = "iconv"))]
 extern "C" {
     pub fn iconv_open(tocode: *const ::c_char, fromcode: *const ::c_char) -> iconv_t;