rustc panics if the terminal's terminfo is invalid

[anachrome]

If the terminfo for my terminal is malformed, rustc panics with

thread '<main>' panicked at 'assertion failed: `(left == right)` (left: `0`, right: `2`)', /home/rustbuild/src/rust-buildbot/slave/stable-dist-rustc-linux/build/src/libterm/terminfo/parser/compiled.rs:315

The simplest reproduction is

touch ~/.terminfo/r/rxvt-unicode-256color

or whatever the $TERM variable is.

[bluss]

It looks like this is fixed in "upstream" libterm, so requires import from there.

[brson]

Fixed. Needs test.

[Mark-Simulacrum]

I don't really think this needs a test or at least not inside rustc itself; closing.