Windows build fails during source file copying phase

[jdm]

I get a panic in

mozjs/build.rs

Line 407 in 618398c

fs::copy(&source, &target).expect("could not copy file");

after modifying makefile.cargo and rebuilding.

[jdm]

I think we're hitting some kind of path limit:
This works - copying "mozjs\\js\\src\\tests\\test262\\language\\block-scope\\syntax\\redeclaration\\fn-scope-var-name-redeclaration-attempt-with-var.js" to "C:\\Users\\image\\servo-g-streamer\\target\\x86_64-uwp-windows-msvc\\release\\build\\mozjs_sys-a12625fb54d6148d\\out\\mozjs\\js\\src\\tests\\test262\\language\\block-scope\\syntax\\redeclaration\\fn-scope-var-name-redeclaration-attempt-with-var.js"
This fails - copying "mozjs\\js\\src\\tests\\test262\\language\\block-scope\\syntax\\redeclaration\\function-declaration-attempt-to-redeclare-with-var-declaration-nested-in-function.js" to "C:\\Users\\image\\servo-g-streamer\\target\\x86_64-uwp-windows-msvc\\release\\build\\mozjs_sys-a12625fb54d6148d\\out\\mozjs\\js\\src\\tests\\test262\\language\\block-scope\\syntax\\redeclaration\\function-declaration-attempt-to-redeclare-with-var-declaration-nested-in-function.js"

[jdm]

thread 'main' panicked at 'could not copy file: Os { code: 3, kind: NotFound, message: "The system cannot find the path specified." }', src\libcore\result.rs:1189:5

[jdm]

I made progress by prepending \\?\ to the destination path before the copying, then replacing that string in the src and build directory paths before invoking configure. However, then things broke inside the python configuration process that didn't make sense to me and I gave up and reverted to an earlier working version of this repo.

[jdm]

rust-lang/rust#67403
<nox> jdm: Feel free to revert. My automated vendoring stuff properly avoid generating .pyc files and does not build psutil at all.

[jdm]

#209 is the triggering PR.