You have to provide the source code for the version of the library you’re linking somewhere. So basically if you ship a static linked glibc executable, you need to provide the source code for the glibc part that you included. I think the actual ideal way to distribute it would be to not statically link it and instead deliver a shared library bundled with your application.
It should be noted that statically linking against an LGPL library does still come with some constraints. https://www.gnu.org/licenses/gpl-faq.html#LGPLStaticVsDynamic
You have to provide the source code for the version of the library you’re linking somewhere. So basically if you ship a static linked glibc executable, you need to provide the source code for the glibc part that you included. I think the actual ideal way to distribute it would be to not statically link it and instead deliver a shared library bundled with your application.