`-msvc` distribution has unused import libraries

[retep998]

Currently in the binary distributions for the -msvc packages, the bin folder has import libraries (.dll.lib) for all the DLLs there even though they are never linked to and could be removed to save some space.

[retep998]

There are 9.53MB of .dll.lib files in the bin folder for x86_64-pc-windows-msvc, so some real savings could be had here.

[steveklabnik]

Triage: i don't believe we've made any changes here

[ChrisDenton]

This is "solved" in the sense that the bin folder no longer has any .dll.lib files. And the default install (via rustup) only has an std .dll.lib in the lib directory (which I believe is necessary for dynamic linking std).

The rustc-dev component has more in the lib directory. Which isn't installed by rustup by default but is often wanted for the sake of rust-analyzer:

> fd --glob *.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\displaydoc-50af9f3b461c50d7.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\derive_where-206786c695a9dc16.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\derive_setters-a2f1ec4ed87dfbc7.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\darling_macro-f87e03ec2d819174.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\icu_provider_macros-e131c148f308f71a.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\zerovec_derive-695483c3dcc03934.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\zerofrom_derive-e1e48a815bb69c9b.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\zerocopy_derive-27714ff9c04ef83d.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\yoke_derive-39051f0a587115c1.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\windows_interface-347768d48a11878b.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\windows_implement-097e354d91641b9d.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\unic_langid_macros_impl-894edf185f03f9d0.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\tracing_attributes-d58a2c7882daed23.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\time_macros-20cac86208b0bcab.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\thiserror_impl-f440f8b09529953d.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\std-d2406463b94cbd40.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\serde_derive-eb51b2ffc4fba3a5.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\rustc_type_ir_macros-4dfe615a35adf301.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\rustc_macros-590be8bdb48ccbc3.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\rustc_index_macros-cc64c85948f697cc.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\rustc_fluent_macro-b345195c88567b14.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\rustc_driver-c6b42fc3dcb03cd3.dll.lib
lib\rustlib\x86_64-pc-windows-msvc\lib\proc_macro_hack-5788a2919223a19c.dll.lib

I'm guessing rustc_driver is, like std, necessary because it can be used by other tools. I'm not sure about the others. They look more internal.