Need for `use libc::` in `master`

[finalyards]

Bug description

Using esp-idf-sys via a GitHub link, to get 6.0.1 support, I noticed the following.

Build fails with a number of esp-idf-sys specific details (below).

I'll be making a PR for this - the fix is trivial - but wanted to ask first about your ideas/opinions.

To Reproduce

Unfortunately, no public repo (yet), no knowledge how to reproduce. But I'll attempt a fix in my fork and see it from there..

Expected behavior

I can use esp-idf-sys with both ESP-IDF 5.5.4 and 6.0.1.

Environment

Complex. :(

Attachment - build output

error[E0425]: cannot find value `MSG_DONTROUTE` in module `sys`
    --> /home/ubuntu/.cargo/git/checkouts/esp-idf-sys-1f365e3f54debd76/eaf69b2/src/checks/libc.rs:108:18
     |
  12 |                 sys::$ident as i64 == libc::$ident as i64,
     |                      ------ due to this macro variable
...
 108 | check_constants!(MSG_DONTROUTE);
     |                  ^^^^^^^^^^^^^
     |
    ::: /home/ubuntu/target/riscv32imac-esp-espidf/release/build/esp-idf-sys-4544fc084c88a572/out/bindings.rs:4719:1
     |
4719 | pub const SO_DONTROUTE: u32 = 16;
     | --------------------------------- similarly named constant `SO_DONTROUTE` defined here
     |
help: a constant with a similar name exists
     |
 108 - check_constants!(MSG_DONTROUTE);
 108 + check_constants!(SO_DONTROUTE);
     |
help: consider importing this constant
     |
   5 + use libc::MSG_DONTROUTE;
     |

error[E0425]: cannot find value `MSG_EOR` in module `sys`
    --> /home/ubuntu/.cargo/git/checkouts/esp-idf-sys-1f365e3f54debd76/eaf69b2/src/checks/libc.rs:114:18
     |
  12 |                 sys::$ident as i64 == libc::$ident as i64,
     |                      ------ due to this macro variable
...
 114 | check_constants!(MSG_EOR);
     |                  ^^^^^^^
     |
    ::: /home/ubuntu/target/riscv32imac-esp-espidf/release/build/esp-idf-sys-4544fc084c88a572/out/bindings.rs:4754:1
     |
4754 | pub const MSG_MORE: u32 = 16;
     | ----------------------------- similarly named constant `MSG_MORE` defined here
     |
help: a constant with a similar name exists
     |
 114 - check_constants!(MSG_EOR);
 114 + check_constants!(MSG_MORE);
     |
help: consider importing this constant
     |
   5 + use libc::MSG_EOR;
     |

error[E0425]: cannot find value `SOMAXCONN` in module `sys`
   --> /home/ubuntu/.cargo/git/checkouts/esp-idf-sys-1f365e3f54debd76/eaf69b2/src/checks/libc.rs:134:18
    |
 12 |                 sys::$ident as i64 == libc::$ident as i64,
    |                      ------ due to this macro variable
...
134 | check_constants!(SOMAXCONN);
    |                  ^^^^^^^^^ not found in `sys`
    |
help: consider importing this constant
    |
  5 + use libc::SOMAXCONN;
    |

error[E0425]: cannot find value `IPV6_UNICAST_HOPS` in module `sys`
    --> /home/ubuntu/.cargo/git/checkouts/esp-idf-sys-1f365e3f54debd76/eaf69b2/src/checks/libc.rs:432:18
     |
  12 |                 sys::$ident as i64 == libc::$ident as i64,
     |                      ------ due to this macro variable
...
 432 | check_constants!(IPV6_UNICAST_HOPS);
     |                  ^^^^^^^^^^^^^^^^^
     |
    ::: /home/ubuntu/target/riscv32imac-esp-espidf/release/build/esp-idf-sys-4544fc084c88a572/out/bindings.rs:3807:1
     |
3807 | pub const IPV6_MULTICAST_HOPS: u32 = 769;
     | ----------------------------------------- similarly named constant `IPV6_MULTICAST_HOPS` defined here
     |
help: a constant with a similar name exists
     |
 432 - check_constants!(IPV6_UNICAST_HOPS);
 432 + check_constants!(IPV6_MULTICAST_HOPS);
     |
help: consider importing this constant
     |
   5 + use libc::IPV6_UNICAST_HOPS;
     |

error[E0425]: cannot find value `NI_MAXHOST` in module `sys`
   --> /home/ubuntu/.cargo/git/checkouts/esp-idf-sys-1f365e3f54debd76/eaf69b2/src/checks/libc.rs:451:18
    |
 12 |                 sys::$ident as i64 == libc::$ident as i64,
    |                      ------ due to this macro variable
...
451 | check_constants!(NI_MAXHOST);
    |                  ^^^^^^^^^^ not found in `sys`
    |
help: consider importing this constant
    |
  5 + use libc::NI_MAXHOST;
    |

error[E0425]: cannot find value `NI_MAXSERV` in module `sys`
   --> /home/ubuntu/.cargo/git/checkouts/esp-idf-sys-1f365e3f54debd76/eaf69b2/src/checks/libc.rs:452:18
    |
 12 |                 sys::$ident as i64 == libc::$ident as i64,
    |                      ------ due to this macro variable
...
452 | check_constants!(NI_MAXSERV);
    |                  ^^^^^^^^^^ not found in `sys`
    |
help: consider importing this constant
    |
  5 + use libc::NI_MAXSERV;
    |

error[E0425]: cannot find value `NI_NUMERICSERV` in module `sys`
    --> /home/ubuntu/.cargo/git/checkouts/esp-idf-sys-1f365e3f54debd76/eaf69b2/src/checks/libc.rs:456:18
     |
  12 |                 sys::$ident as i64 == libc::$ident as i64,
     |                      ------ due to this macro variable
...
 456 | check_constants!(NI_NUMERICSERV);
     |                  ^^^^^^^^^^^^^^
     |
    ::: /home/ubuntu/target/riscv32imac-esp-espidf/release/build/esp-idf-sys-4544fc084c88a572/out/bindings.rs:4816:1
     |
4816 | pub const AI_NUMERICSERV: u32 = 8;
     | ---------------------------------- similarly named constant `AI_NUMERICSERV` defined here
     |
help: a constant with a similar name exists
     |
 456 - check_constants!(NI_NUMERICSERV);
 456 + check_constants!(AI_NUMERICSERV);
     |
help: consider importing this constant
     |
   5 + use libc::NI_NUMERICSERV;
     |

error[E0425]: cannot find value `NI_DGRAM` in module `sys`
   --> /home/ubuntu/.cargo/git/checkouts/esp-idf-sys-1f365e3f54debd76/eaf69b2/src/checks/libc.rs:457:18
    |
 12 |                 sys::$ident as i64 == libc::$ident as i64,
    |                      ------ due to this macro variable
...
457 | check_constants!(NI_DGRAM);
    |                  ^^^^^^^^ not found in `sys`
    |
help: consider importing this constant
    |
  5 + use libc::NI_DGRAM;
    |

For more information about this error, try `rustc --explain E0425`.
error: could not compile `esp-idf-sys` (lib) due to 8 previous errors

[finalyards]

Not sure it's upstream, after all. Investigating..