perf demangle-rust: Add rustc-demangle C demangler

Imported at commit 80e40f57d99f ("add comment about finding latest
version of code") from:

https://github.com/rust-lang/rustc-demangle/blob/main/crates/native-c/src/demangle.c
https://github.com/rust-lang/rustc-demangle/blob/main/crates/native-c/include/demangle.h

There is discussion of this issue motivating the import in:

rust-lang/rust#60705
https://lore.kernel.org/lkml/[email protected]/

The SPDX lines reflect the dual license Apache-2 or MIT in:

https://github.com/rust-lang/rustc-demangle/blob/main/README.md

Following Migual Ojeda's suggestion comments were added on copyright and
keeping the code in sync with upstream.

The files are renamed as perf supports multiple demanglers and so
demangle as a name would be overloaded.

The work here was done by Ariel Ben-Yehuda <[email protected]> and I
am merely importing it as discussed in the rust-lang issue.

Reviewed-by: Miguel Ojeda <[email protected]>
Signed-off-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alex Gaynor <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Alice Ryhl <[email protected]>
Cc: Andreas Hindborg <[email protected]>
Cc: Ariel Ben-Yehuda <[email protected]>
Cc: Benno Lossin <[email protected]>
Cc: Bill Wendling <[email protected]>
Cc: Björn Roy Baron <[email protected]>
Cc: Boqun Feng <[email protected]>
Cc: Daniel Xu <[email protected]>
Cc: Danilo Krummrich <[email protected]>
Cc: Gary Guo <[email protected]>
Cc: Howard Chu <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiapeng Chong <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Justin Stitt <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Ravi Bangoria <[email protected]>
Cc: Stephen Brennan <[email protected]>
Cc: Trevor Gross <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: captain5050