- Runs a closure and catches unwinds triggered by fatal errors. 
- Variant of - catch_fatal_errorsfor the- interface::Resultreturn type
that also computes the exit code.
 
- Show help for flag categories shared between rustdoc and rustc. 
- Write to stdout lint command options, together with a list of all available lints 
- Process command line options. Emits messages as appropriate. If compilation
should continue, returns a getopts::Matches object parsed from args,
otherwise returns - None.
 
- This allows tools to enable rust logging without having to magically match rustcβs
tracing crate version. In contrast to - init_rustc_env_loggerit allows you to choose
the values directly rather than having to set an environment variable.
 
- This allows tools to enable rust logging without having to magically match rustcβs
tracing crate version. 
- Install our usual  - ctrlc-  handler, which sets  - rustc_const_eval::CTRL_C_RECEIVED- .
Making this handler optional lets tools can install a different handler, if they wish. 
- Installs a panic hook that will print the ICE message on unexpected panics. 
- Prints the ICE message, including query stack, but without backtrace. 
- If color is always or auto, print formatted & colorized markdown. If color is never or
if formatted printing fails, print the raw text.