Issue with running cargo run --example test_window

[ghost]

[zukkoe@fedora imgui-rs-main]$ cargo run --example test_window
   Compiling servo-fontconfig-sys v5.1.0
error: failed to run custom build command for `servo-fontconfig-sys v5.1.0`

Caused by:
  process didn't exit successfully: `/home/zukkoe/Documents/RustProjects/imgui-rs-main/target/debug/build/servo-fontconfig-sys-df295a0f2c3d1bcc/build-script-build` (exit status: 101)
  --- stdout
  cargo:rerun-if-env-changed=FONTCONFIG_NO_PKG_CONFIG
  cargo:rerun-if-env-changed=PKG_CONFIG_x86_64-unknown-linux-gnu
  cargo:rerun-if-env-changed=PKG_CONFIG_x86_64_unknown_linux_gnu
  cargo:rerun-if-env-changed=HOST_PKG_CONFIG
  cargo:rerun-if-env-changed=PKG_CONFIG
  cargo:rerun-if-env-changed=FONTCONFIG_STATIC
  cargo:rerun-if-env-changed=FONTCONFIG_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

  --- stderr
  thread 'main' panicked at '`PKG_CONFIG_ALLOW_SYSTEM_CFLAGS="1" PKG_CONFIG_ALLOW_SYSTEM_LIBS="1" "pkg-config" "--libs" "--cflags" "fontconfig" "fontconfig >= 2.11.1"` did not exit successfully: exit status: 1
  error: could not find system library 'fontconfig' required by the 'servo-fontconfig-sys' crate

  --- stderr
  Package fontconfig was not found in the pkg-config search path.
  Perhaps you should add the directory containing `fontconfig.pc'
  to the PKG_CONFIG_PATH environment variable
  Package 'fontconfig', required by 'virtual:world', not found
  Package 'fontconfig', required by 'virtual:world', not found
  ', /home/zukkoe/.cargo/registry/src/github.com-1ecc6299db9ec823/servo-fontconfig-sys-5.1.0/build.rs:34:17
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

[dbr]

Hmm, the error is due to missing the fontconfig library. Simplest solution is to install that library (libfontconfig-dev on Ubuntu)

However it's a bit strange that it is required - the dependency comes from

winit -> sctk-adwaita -> crossfont -> servo-fontconfig -> servo-fontconfig-sys

which is behind a default sctk-adwaita feature in winit and we specify default-features = false in imgui-winit-support. It's presumably coming from some other dependency on winit but not immediately obvious where