`freetype` feature does not compile on Windows: tries to call non-existent `pkg-config`

[ctrlcctrlv]

error: failed to run custom build command for `imgui-sys v0.8.1-alpha.0 (https://github.com/imgui-rs/imgui-rs#6faa7f09)`

Caused by:
  process didn't exit successfully: `D:\a\glif\glif\target\debug\build\imgui-sys-98982d076e541193\build-script-build` (exit code: 101)
  --- stdout
  cargo:THIRD_PARTY=C:\Users\runneradmin\.cargo\git\checkouts\imgui-rs-61ccdc9370f94e57\6faa7f0\imgui-sys\third-party
  cargo:DEFINE_IMGUI_USE_WCHAR32=
  cargo:DEFINE_CIMGUI_NO_EXPORT=
  cargo:DEFINE_IMGUI_DISABLE_WIN32_FUNCTIONS=
  cargo:DEFINE_IMGUI_DISABLE_OSX_FUNCTIONS=
  cargo:rerun-if-env-changed=FREETYPE2_NO_PKG_CONFIG
  cargo:rerun-if-env-changed=PKG_CONFIG_x86_64-pc-windows-msvc
  cargo:rerun-if-env-changed=PKG_CONFIG_x86_64_pc_windows_msvc
  cargo:rerun-if-env-changed=HOST_PKG_CONFIG
  cargo:rerun-if-env-changed=PKG_CONFIG
  cargo:rerun-if-env-changed=FREETYPE2_STATIC
  cargo:rerun-if-env-changed=FREETYPE2_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-pc-windows-msvc
  cargo:rerun-if-env-changed=PKG_CONFIG_PATH_x86_64_pc_windows_msvc
  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-pc-windows-msvc
  cargo:rerun-if-env-changed=PKG_CONFIG_LIBDIR_x86_64_pc_windows_msvc
  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-pc-windows-msvc
  cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR_x86_64_pc_windows_msvc
  cargo:rerun-if-env-changed=HOST_PKG_CONFIG_SYSROOT_DIR
  cargo:rerun-if-env-changed=PKG_CONFIG_SYSROOT_DIR

  --- stderr
  thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: "Could not run `\"pkg-config\" \"--libs\" \"--cflags\" \"freetype2\"`\nThe pkg-config command could not be found.\n\nMost likely, you need to install a pkg-config package for your OS.\n\nIf you've already installed it, ensure the pkg-config command is one of the\ndirectories in the PATH environment variable.\n\nIf you did not expect this build to link to a pre-installed system library,\nthen check documentation of the imgui-sys crate for an option to\nbuild the library from source, or disable features or dependencies\nthat require pkg-config."', C:\Users\runneradmin\.cargo\git\checkouts\imgui-rs-61ccdc9370f94e57\6faa7f0\imgui-sys\build.rs:54:72
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
warning: build failed, waiting for other jobs to finish...
error: build failed
Error: Process completed with exit code 1.

[thomcc]

Ah, this is bad, sorry. I'll see if I can get a patch up tomorrow or so.

[dbr]

I think this overlaps significantly with #566 - it's unclear to me what the correct way is to make the freetype library available on Windows. On linux it just requires apt install libfreetype6-dev, but on Windows, :shrug: