7643: Automatically detect the rustc-src directory (fixes#3517) r=matklad a=bnjbvr
If the configured rustcSource was not set, then try to automatically
detect a source for the sysroot rustc directory.
I wasn't sure how to do it in the case of the project.json file, though.
7663: Tolerate spaces in nix binary patching r=matklad a=CertainLach
If path to original file contains space (I.e on code insiders, where
default data directory is ~/Code - Insiders/), then there is syntax
error evaluating src arg.
Instead pass path as str, and coerce to path back in nix expression
Co-authored-by: Benjamin Bouvier <public@benj.me>
Co-authored-by: Yaroslav Bolyukin <iam@lach.pw>
d50a37d3aa