I am developing a proprietary (non-open source) commercial application that depends (both directly and indirectly through direct dependencies) on some LGPLv2.1+ libraries (specifically some MinGW64 libraries from MSYS2).
I have understood that if I distribute the libraries as binary DLLs, I must provide notice of the usage of the LGPL libraries and offer to provide source code for them. This is cumbersome, as I am not in fact in possession of the source code. I would have to download the MSYS2 build scripts and all related source code, and make sure that I can produce the same binaries with them.
If instead I write a script that downloads the binary packages from the MSYS2 repositories and tell the users of my software to run it, them I think that I am not distributing the libraries myself. Instead, I would distribute my dynamically linked executable, and the downloader script.
Having read section 5 of the LGPLv2.1, I am unsure whether the executable I want to distribute would count as a "work that uses the Library", and unsure how the other paragraphs of section 5 affect the situation.
Do I have to offer source code or mention the LGPL libraries? What other obligations from the LGPL am I left with?