README indicates powerpc64-unknown-linux-gnu is present, but cross disagrees

[xobs]

According to the README, I can build with targets such as powerpc64-unknown-linux-gnu. However, I'm tracking down an issue where cc-rs has stopped building on this particular target on CI.

In the build output, it says:

...
+cross build --target powerpc64-unknown-linux-gnu
info: downloading component 'rust-std' for 'powerpc64-unknown-linux-gnu'
info: installing component 'rust-std' for 'powerpc64-unknown-linux-gnu'
Warning: `cross` does not provide a Docker image for target powerpc64-unknown-linux-gnu, specify a custom image in `Cross.toml`. Falling back to `cargo` on the host.
    Updating crates.io index
 Downloading crates ...
  Downloaded autocfg v0.1.5
...
CRATE_CC_NO_DEFAULTS = None
DEBUG = Some("true")
CARGO_CFG_TARGET_FEATURE = None
running: "powerpc-linux-gnu-gcc" "-O0" "-ffunction-sections" "-fdata-sections" "-fPIC" "-g" "-fno-omit-frame-pointer" "-m64" "-I" "." "-I" "libusb/libusb" "-Wall" "-Wextra" "-DOS_LINUX=1" "-DHAVE_ASM_TYPES_H=1" "-DHAVE_LINUX_NETLINK_H=1" "-DHAVE_SYS_SOCKET_H=1" "-DUSBI_TIMERFD_AVAILABLE=1" "-DPOLL_NFDS_TYPE=nfds_t" "-D_GNU_SOURCE=1" "-DHAVE_DLFCN_H=1" "-DHAVE_GETTIMEOFDAY=1" "-DHAVE_INTTYPES_H=1" "-DHAVE_MEMORY_H=1" "-DHAVE_POLL_H=1" "-DHAVE_STDINT_H=1" "-DHAVE_STDLIB_H=1" "-DHAVE_STRINGS_H=1" "-DHAVE_STRING_H=1" "-DHAVE_STRUCT_TIMESPEC=1" "-DHAVE_SYS_STAT_H=1" "-DHAVE_SYS_TIME_H=1" "-DHAVE_SYS_TYPES_H=1" "-DHAVE_UNISTD_H=1" "-DPOLL_NFDS_TYPE=nfds_t" "-DSTDC_HEADERS=1" "-DTHREADS_POSIX=1" "-DDEFAULT_VISIBILITY=__attribute__((visibility(\"default\")))" "-o" "/home/travis/build/litex-hub/wishbone-utils/wishbone-tool/target/powerpc64-unknown-linux-gnu/debug/build/libusb-sys-wishbone-tool-6a31a5e230c183a0/out/libusb/libusb/os/linux_netlink.o" "-c" "libusb/libusb/os/linux_netlink.c"
--- stderr
thread 'main' panicked at '
Internal error occurred: Failed to find tool. Is `powerpc-linux-gnu-gcc` installed?
', /home/travis/.cargo/registry/src/github.com-1ecc6299db9ec823/cc-1.0.35/src/lib.rs:2398:5
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Is the README out of date? What's causing powerpc-linux-gnu-gcc to not be installed?

[reitermarkus]

Is the README out of date?

Yes, seems like this was missed.

The powerpc64-unknown-linux-gnu image was disabled because it kept breaking and it currently doesn't build anymore.

[asomers]

Can you at least fix the README?

[Alexhuszagh]

This image has been re-enabled, and a quick check shows that this builds, however, it does not support C dependencies (with a glibc version error):

cargo install cross --git https://github.com/cross-rs/cross
cargo init --bin hello
cd hello
cross run --target powerpc64-unknown-linux-gnu