build_cfg is used at run time in 1 crate (of which 1 optionally). It's used at build time in 8 crates (3 directly). It's used only as a dev dependency in 1 crate.

Depender (with downloads and own rev deps) build_cfg version
2.1K 6 windows_exe_info optional ^1.1.0
170 clippers build ^1
100 1 prefer-dynamic build ^1
1 clip_img build ^1.1.0