Title: Build fails on clean Debian: missing libfontconfig-dev not mentioned in README

[aajll]

Hi, thanks for the tool!

I followed the README on a fairly clean Debian 13 box and cargo install --path apps/datasheet-cli failed with:

error: failed to run custom build command for `yeslogic-fontconfig-sys v6.0.1`

Caused by:
  process didn't exit successfully: `/home/acid/Workspace/third_party/datasheet-cli/target/release/build/yeslogic-fontconfig-sys-9a988a9c0bde9ed0/build-script-build` (exit status: 101)
  --- stdout
  cargo:rerun-if-env-changed=RUST_FONTCONFIG_DLOPEN
  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' (1398389) panicked at /home/acid/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/yeslogic-fontconfig-sys-6.0.1/build.rs:8:48:
  called `Result::unwrap()` on an `Err` value: "\npkg-config exited with status code 1\n> PKG_CONFIG_ALLOW_SYSTEM_LIBS=1 PKG_CONFIG_ALLOW_SYSTEM_CFLAGS=1 pkg-config --libs --cflags fontconfig\n\npkg-config output:\n  Package fontconfig was not found in the pkg-config search path.\n  Perhaps you should add the directory containing `fontconfig.pc'\n  to the PKG_CONFIG_PATH environment variable\n  Package 'fontconfig', required by 'virtual:world', not found\n\nThe system library `fontconfig` required by crate `yeslogic-fontconfig-sys` was not found.\nThe file `fontconfig.pc` needs to be installed and the PKG_CONFIG_PATH environment variable must contain its parent directory.\nThe PKG_CONFIG_PATH environment variable is not set.\n\nHINT: if you have installed the library, try setting PKG_CONFIG_PATH to the directory containing `fontconfig.pc`.\n"
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
warning: build failed, waiting for other jobs to finish...
error: failed to compile `datasheet-cli v0.1.10 (/home/acid/Workspace/third_party/datasheet-cli/apps/datasheet-cli)`, intermediate artifacts can be found at `/home/acid/Workspace/third_party/datasheet-cli/target`.
To reuse those artifacts with a future compilation, set the environment variable `CARGO_BUILD_BUILD_DIR` to that path.

The system library fontconfig required by crate yeslogic-fontconfig-sys was not found.
The file fontconfig.pc needs to be installed and the PKG_CONFIG_PATH environment variable must contain its parent directory.

It comes in through mupdf's default system-fonts feature:

datasheet-cli → mupdf 0.7 → font-kit 0.14 → yeslogic-fontconfig-sys

Running sudo apt install libfontconfig-dev fixed it and the build then completed fine. CI probably doesn't catch it because the GitHub Ubuntu runners already have the fontconfig dev files.