menu example is not working for me#206

I'm running NixOS 21.05, but the menu example is not working. (I tried, because I have problems in my project using menu). ``` nix-shell -p --run "cargo run --example ex_5" Compiling libc v0.2.102 Compiling pkg-config v0.3.19 Compiling cc v1.0.70 Compiling ncurses v5.100.0 (/home/palo/dev/ncurses-rs) warning: variable does not need to be mutable --> build.rs:79:9 | 79 | let mut build = cc::Build::new(); | ----^^^^^ | | | help: remove this `mut` | = note: `#[warn(unused_mut)]` on by default warning: variable does not need to be mutable --> build.rs:104:9 | 104 | let mut build = cc::Build::new(); | ----^^^^^ | | | help: remove this `mut` warning: unused `Result` that must be used --> build.rs:95:5 | 95 | file.write_all(&consts.stdout); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: `#[warn(unused_must_use)]` on by default = note: this `Result` may be an `Err` variant, which should be handled warning: unused `Result` that must be used --> build.rs:120:5 | 120 | file.write_all(&consts.stdout); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: this `Result` may be an `Err` variant, which should be handled warning: `ncurses` (build script) generated 4 warnings error: failed to run custom build command for `ncurses v5.100.0 (/home/palo/dev/ncurses-rs)` Caused by: process didn't exit successfully: `/home/palo/dev/ncurses-rs/target/debug/build/ncurses-09f72d651aec0eab/build-script-build` (exit status: 101) --- stdout cargo:rerun-if-env-changed=PKG_CONFIG_PATH cargo:rerun-if-env-changed=NCURSES5_NO_PKG_CONFIG cargo:rerun-if-env-changed=PKG_CONFIG cargo:rerun-if-env-changed=NCURSES5_STATIC cargo:rerun-if-env-changed=NCURSES5_DYNAMIC cargo:rerun-if-env-changed=PKG_CONFIG_ALL_STATIC cargo:rerun-if-env-changed=PKG_CONFIG_ALL_DYNAMIC cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64-unknown-linux-gnu cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64_unknown_linux_gnu cargo:rerun-if-env-changed=HOST_PKG_CONFIG_PATH cargo:rerun-if-env-changed=PKG_CONFIG_PATH cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64-unknown-linux-gnu cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64_unknown_linux_gnu cargo:rerun-if-env-changed=HOST_PKG_CONFIG_LIBDIR cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64-unknown-linux-gnu cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64_unknown_linux_gnu cargo:rerun-if-env-changed=HOST_PKG_CONFIG_SYSROOT_DIR cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR cargo:rerun-if-env-changed=NCURSES_NO_PKG_CONFIG cargo:rerun-if-env-changed=PKG_CONFIG cargo:rerun-if-env-changed=NCURSES_STATIC cargo:rerun-if-env-changed=NCURSES_DYNAMIC cargo:rerun-if-env-changed=PKG_CONFIG_ALL_STATIC cargo:rerun-if-env-changed=PKG_CONFIG_ALL_DYNAMIC cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64-unknown-linux-gnu cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64_unknown_linux_gnu cargo:rerun-if-env-changed=HOST_PKG_CONFIG_PATH cargo:rerun-if-env-changed=PKG_CONFIG_PATH cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64-unknown-linux-gnu cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64_unknown_linux_gnu cargo:rerun-if-env-changed=HOST_PKG_CONFIG_LIBDIR cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64-unknown-linux-gnu cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64_unknown_linux_gnu cargo:rerun-if-env-changed=HOST_PKG_CONFIG_SYSROOT_DIR cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR cargo:rustc-link-lib=ncurses OPT_LEVEL = Some("0") TARGET = Some("x86_64-unknown-linux-gnu") HOST = Some("x86_64-unknown-linux-gnu") CC_x86_64-unknown-linux-gnu = None CC_x86_64_unknown_linux_gnu = None HOST_CC = None CC = Some("gcc") CFLAGS_x86_64-unknown-linux-gnu = None CFLAGS_x86_64_unknown_linux_gnu = None HOST_CFLAGS = None CFLAGS = None CRATE_CC_NO_DEFAULTS = None DEBUG = Some("true") CARGO_CFG_TARGET_FEATURE = Some("fxsr,sse,sse2") --- stderr In file included from /nix/store/q141hd8jl7in5223jmf7kmx9h517km4p-glibc-2.32-54-dev/include/assert.h:35, from /home/palo/dev/ncurses-rs/target/debug/build/ncurses-d3ec6d0e162c87ed/out/chtype_size.c:2: /nix/store/q141hd8jl7in5223jmf7kmx9h517km4p-glibc-2.32-54-dev/include/features.h:397:4: warning: #warning _FORTIFY_SOURCE requires compiling with optimization (-O) [-Wcpp] 397 | # warning _FORTIFY_SOURCE requires compiling with optimization (-O) | ^~~~~~~ /home/palo/dev/ncurses-rs/target/debug/build/ncurses-d3ec6d0e162c87ed/out/chtype_size.c:6:10: fatal error: ncurses.h: No such file or directory 6 | #include <ncurses.h> | ^~~~~~~~~~~ compilation terminated. thread 'main' panicked at 'assertion failed: command.status().expect(\"compilation failed\").success()', build.rs:166:5 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace ```