Problem

We normally don't include xxd but we do in Windows. Currently we fetch a prebuilt xxd.exe from https://github.com/neovim/deps/blob/master/opt/xxd.exe , but this has the following problems:

• it's not ideal in terms of obviousness
• we are missing some updates to xxd.c since then
• it's clumsy to update stuff in https://github.com/neovim/deps , so we only want to use it as a last resort

#36363 demonstrates that these tiny one-file C sources are easy to vendor, and also have some advantages (analyzer checks). Our build system is also setup to easily build and include third-party vendored things.

Expected behavior

Similar to tee.c #36363 , we can include xxd.c :

https://github.com/vim/vim/blob/77cfc49060a50daefd1675b8a1dece0e6e943384/src/xxd/xxd.c