Support linking/usage of libraw provided by the system

[tenzap]

I'm trying to package your crate for inclusion in Debian. However I noticed that you use/build a local copy of libraw library. This can't be used as such in Debian which already ships the libraw library. In Debian we prefer to use the system library. Would you add support for linking/using the libraw library of the system?

This would also permit your code to be linked to the version preferred by the user. Currently Debian ships libraw 0.21.2 which is newer than the version you use in your code which is 0.20.1.

[paolobarbolini]

I'll try looking into it but I can't guarantee how much I'll take. Also I'll have to look into whether https://github.com/LibRaw/LibRaw/pull/348 was re-included into 0.21, because in 0.20 it was considered a breaking change in the ABI and it was reverted. The copy in the git submodules is from before the revert.

[tenzap]

I tried to write patches, but since I don't know rust language, you may want to check or rewrite them. By doing so I removed the bindgen feature which I made default. This patch is probably not suitable for all OS.

In libraw-rs-sys https://salsa.debian.org/rust-team/debcargo-conf/-/blob/6432d1b310cc21e2f5fe9d34469de5cb620a4ffa/src/libraw-rs-sys/debian/patches/fix_bindgen_feature.patch https://salsa.debian.org/rust-team/debcargo-conf/-/blob/6432d1b310cc21e2f5fe9d34469de5cb620a4ffa/src/libraw-rs-sys/debian/patches/link_to_system_libraw.patch

In libraw-rs https://salsa.debian.org/rust-team/debcargo-conf/-/blob/6432d1b310cc21e2f5fe9d34469de5cb620a4ffa/src/libraw-rs/debian/patches/remove_bindgen_feature.patch