Revert RUSTFLAGS removal

[Meziu]

After my changes to the RUSTFLAGS before 0.1.0, I had tested ctru-rs to ensure known-to-not-work examples would in fact compile. However, I mistakenly did not test network-related examples, and I only now notice that those RUSTFLAGS changes are required to link all network related functions.

= note: /opt/devkitpro/devkitARM/bin/../lib/gcc/arm-none-eabi/13.1.0/../../../../arm-none-eabi/bin/ld: /Users/andreaciliberti/Desktop/Programming/Rust/rust-3ds/ctru-rs/target/armv6k-nintendo-3ds/debug/deps/libstd-2aab5dc9bae7bd35.rlib(std-2aab5dc9bae7bd35.std.b2cd8dee9fb32859-cgu.14.rcgu.o): in function `std::sys::unix::net::cvt_gai':
          /Users/andreaciliberti/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/sys/unix/net.rs:49: undefined reference to `gai_strerror'
          /opt/devkitpro/devkitARM/bin/../lib/gcc/arm-none-eabi/13.1.0/../../../../arm-none-eabi/bin/ld: /Users/andreaciliberti/Desktop/Programming/Rust/rust-3ds/ctru-rs/target/armv6k-nintendo-3ds/debug/deps/libstd-2aab5dc9bae7bd35.rlib(std-2aab5dc9bae7bd35.std.b2cd8dee9fb32859-cgu.14.rcgu.o): in function `std::sys::unix::net::Socket::recv_with_flags':
          /Users/andreaciliberti/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/sys/unix/net.rs:247: undefined reference to `recv'
          /opt/devkitpro/devkitARM/bin/../lib/gcc/arm-none-eabi/13.1.0/../../../../arm-none-eabi/bin/ld: /Users/andreaciliberti/Desktop/Programming/Rust/rust-3ds/ctru-rs/target/armv6k-nintendo-3ds/debug/deps/libstd-2aab5dc9bae7bd35.rlib(std-2aab5dc9bae7bd35.std.b2cd8dee9fb32859-cgu.14.rcgu.o): in function `std::sys::unix::net::Socket::shutdown':
          /Users/andreaciliberti/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/sys/unix/net.rs:385: undefined reference to `shutdown'
          /opt/devkitpro/devkitARM/bin/../lib/gcc/arm-none-eabi/13.1.0/../../../../arm-none-eabi/bin/ld: /Users/andreaciliberti/Desktop/Programming/Rust/rust-3ds/ctru-rs/target/armv6k-nintendo-3ds/debug/deps/libstd-2aab5dc9bae7bd35.rlib(std-2aab5dc9bae7bd35.std.b2cd8dee9fb32859-cgu.14.rcgu.o): in function `std::sys::unix::net::Socket::set_nonblocking':
          /Users/andreaciliberti/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/sys/unix/net.rs:460: undefined reference to `ioctl'
          /opt/devkitpro/devkitARM/bin/../lib/gcc/arm-none-eabi/13.1.0/../../../../arm-none-eabi/bin/ld: /Users/andreaciliberti/Desktop/Programming/Rust/rust-3ds/ctru-rs/target/armv6k-nintendo-3ds/debug/deps/libstd-2aab5dc9bae7bd35.rlib(std-2aab5dc9bae7bd35.std.b2cd8dee9fb32859-cgu.14.rcgu.o): in function `std::sys::unix::net::Socket::accept::{{closure}}':
          /Users/andreaciliberti/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/sys/unix/net.rs:232: undefined reference to `accept'
          /opt/devkitpro/devkitARM/bin/../lib/gcc/arm-none-eabi/13.1.0/../../../../arm-none-eabi/bin/ld: /Users/andreaciliberti/Desktop/Programming/Rust/rust-3ds/ctru-rs/target/armv6k-nintendo-3ds/debug/deps/libstd-2aab5dc9bae7bd35.rlib(std-2aab5dc9bae7bd35.std.b2cd8dee9fb32859-cgu.14.rcgu.o): in function `std::sys_common::net::setsockopt':
          /Users/andreaciliberti/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/sys_common/net.rs:68: undefined reference to `setsockopt'
          /opt/devkitpro/devkitARM/bin/../lib/gcc/arm-none-eabi/13.1.0/../../../../arm-none-eabi/bin/ld: /Users/andreaciliberti/Desktop/Programming/Rust/rust-3ds/ctru-rs/target/armv6k-nintendo-3ds/debug/deps/libstd-2aab5dc9bae7bd35.rlib(std-2aab5dc9bae7bd35.std.b2cd8dee9fb32859-cgu.14.rcgu.o): in function `<std::sys_common::net::LookupHost as core::ops::drop::Drop>::drop':
          /Users/andreaciliberti/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/sys_common/net.rs:171: undefined reference to `freeaddrinfo'
          /opt/devkitpro/devkitARM/bin/../lib/gcc/arm-none-eabi/13.1.0/../../../../arm-none-eabi/bin/ld: /Users/andreaciliberti/Desktop/Programming/Rust/rust-3ds/ctru-rs/target/armv6k-nintendo-3ds/debug/deps/libstd-2aab5dc9bae7bd35.rlib(std-2aab5dc9bae7bd35.std.b2cd8dee9fb32859-cgu.14.rcgu.o): in function `<std::sys_common::net::LookupHost as core::convert::TryFrom<(&str,u16)>>::try_from::{{closure}}':
          /Users/andreaciliberti/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/sys_common/net.rs:206: undefined reference to `getaddrinfo'
          /opt/devkitpro/devkitARM/bin/../lib/gcc/arm-none-eabi/13.1.0/../../../../arm-none-eabi/bin/ld: /Users/andreaciliberti/Desktop/Programming/Rust/rust-3ds/ctru-rs/target/armv6k-nintendo-3ds/debug/deps/libstd-2aab5dc9bae7bd35.rlib(std-2aab5dc9bae7bd35.std.b2cd8dee9fb32859-cgu.14.rcgu.o): in function `std::sys_common::net::TcpStream::write':
          /Users/andreaciliberti/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/sys_common/net.rs:291: undefined reference to `send'
          /opt/devkitpro/devkitARM/bin/../lib/gcc/arm-none-eabi/13.1.0/../../../../arm-none-eabi/bin/ld: /Users/andreaciliberti/Desktop/Programming/Rust/rust-3ds/ctru-rs/target/armv6k-nintendo-3ds/debug/deps/libstd-2aab5dc9bae7bd35.rlib(std-2aab5dc9bae7bd35.std.b2cd8dee9fb32859-cgu.14.rcgu.o): in function `std::sys_common::net::TcpListener::bind':
          /Users/andreaciliberti/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/sys_common/net.rs:413: undefined reference to `bind'
          /opt/devkitpro/devkitARM/bin/../lib/gcc/arm-none-eabi/13.1.0/../../../../arm-none-eabi/bin/ld: /Users/andreaciliberti/.rustup/toolchains/nightly-x86_64-apple-darwin/lib/rustlib/src/rust/library/std/src/sys_common/net.rs:428: undefined reference to `listen'
          collect2: error: ld returned 1 exit status

It's interesting to note how only networking functions are listed here, even though other functions (e.g. fopen and other fs functions) that are implemented in libctru don't have this issue.

I wonder if including these functions in the upstream newlib (maybe in a similar way to how the pthread functions are filled) would solve the issue...

[ian-h-chamberlain]

Huh, it's surprising that this is needed, but I guess if the std network functions are linked before the final executable (and not discarded) like they would then maybe they need definitions on those symbols.

It would be nice if the new CI you set up caught stuff like this, maybe by trying to build all the examples in ctru-rs or something? I guess it makes more sense for ctru-rs to have its own CI do that, really ...