Need to filter cargo `rerun-if-changed` directives

[yongqli]

Currently running cargo build -vv in highs-sys dir outputs lines such as:

[highs-sys 1.11.0] cargo:rerun-if-changed=/Users/username/Projects/highs-sys/target/debug/build/highs-sys-1c83f0054887d3e0/out/include/highs/interfaces/highs_c_api.h
[highs-sys 1.11.0] cargo:rerun-if-changed=/Users/username/Projects/highs-sys/target/debug/build/highs-sys-1c83f0054887d3e0/out/include/highs/lp_data/HighsCallbackStruct.h
[highs-sys 1.11.0] cargo:rerun-if-changed=/Users/username/Projects/highs-sys/target/debug/build/highs-sys-1c83f0054887d3e0/out/include/highs/util/HighsInt.h
[highs-sys 1.11.0] cargo:rerun-if-changed=/Users/username/Projects/highs-sys/target/debug/build/highs-sys-1c83f0054887d3e0/out/include/highs/HConfig.h
[highs-sys 1.11.0] cargo:rustc-link-search=native=/Users/username/Projects/highs-sys/target/debug/build/highs-sys-1c83f0054887d3e0/out/lib
[highs-sys 1.11.0] cargo:rustc-link-search=native=/Users/username/Projects/highs-sys/target/debug/build/highs-sys-1c83f0054887d3e0/out/lib64

The named files are in the output directory itself, so it will trigger further rebuilds.

The culprit is that autogenerated header files are parsed by bindgen, which will them print the rerun directives due to .parse_callbacks(Box::new(bindgen::CargoCallbacks::new())). As a quick hack commenting out that line fixes the issue, confirming that it is the cause.

I propose that we create a custom version of CargoCallbacks that filters out header files in the output directory itself. I can create pull request if interested.

[lovasoa]

Maybe you should make the pull request directly to bindgen ? This may be useful to others

[yongqli]

See #41

I can try to open a discussion on bindgen, but bindgen is doing exactly what it is being asked to do, which is to name every input it used.