…ntCtxt::new_in_snapshot

This reduces the compiler-doc file from 40K to 36K, a 10% reduction in size.

Set llvm configs when building lld

Several LLVM configs applied when building LLVM should also be applied when building LLD.

For example, without the fix, setting both `llvm.thin-lto=true` and `rust.lld=true` when building on Linux will fail, since we need to manually override the compiler and linker to `clang`, but those will not be used when building LLD, causing link errors.

r? `@jyn514`

…r=jackh726

Use `TraitEngine` in more places that don't specifically need `FulfillmentContext::new_in_snapshot`

Not sure if this change is worthwhile, but couldn't hurt re: chalkification

r? types

…cottmcm

cleanup code w/ pointers in std a little

Use pointer methods (`byte_add`, `null_mut`, etc) to make code in std a little nicer.

…s, r=GuillaumeGomez

rustdoc: use a more compact encoding for source-files.js

This reduces the compiler-doc file from 40K to 36K, a 10% reduction in size.

…Dylan-DPC

Fix typo

r? `@jackh726`