Rollup of 5 pull requests#65604

Closed

Centril wants to merge 11 commits intorust-lang:masterfrom

Centril:rollup-bw7ur3d

Commits on Oct 2, 2019

Inline `ptr::null(_mut)` even in debug builds
tesuji
committed

Commits on Oct 18, 2019

Avoid realloc in `CString::new`
sinkuu
committed

Commits on Oct 19, 2019