rustup.sh / install.sh don't install license documents and thus violate several open source licenses

[nodakai]

$ rust-nightly-x86_64-unknown-linux-gnu/install.sh --prefix=/tmp/xyz
install: looking for install programs 
...
install: /tmp/xyz/lib/libtime-4e7c5e5c.so
install: /tmp/xyz/lib/librustdoc-4e7c5e5c.so
install: /tmp/xyz/share/man/man1/rustc.1
install: /tmp/xyz/share/man/man1/rustdoc.1
install: /tmp/xyz/bin/rust-lldb       
install: /tmp/xyz/bin/rustdoc         
install: /tmp/xyz/bin/rustc           
rust-nightly-x86_64-unknown-linux-gnu/install.sh: 479: rust-nightly-x86_64-unknown-linux-gnu/install.sh: ldconfig: not found
install: WARNING: failed to run ldconfig.
install: WARNING: this may happen when not installing as root and may be fine
install: verifying installed binaries are executable

    Note: please ensure '/tmp/xyz/lib' is added to LD_LIBRARY_PATH

    Rust is ready to roll.            

$ grep -nHr Illinois rust-nightly-x86_64-unknown-linux-gnu/
rust-nightly-x86_64-unknown-linux-gnu/COPYRIGHT:143:    Copyright (c) 2003-2013 University of Illinois at
rust-nightly-x86_64-unknown-linux-gnu/COPYRIGHT:150:        University of Illinois at Urbana-Champaign
rust-nightly-x86_64-unknown-linux-gnu/COPYRIGHT:175:          Illinois at Urbana-Champaign, nor the names of its
rust-nightly-x86_64-unknown-linux-gnu/COPYRIGHT:206:        University of Illinois at Urbana-Champaign
rust-nightly-x86_64-unknown-linux-gnu/COPYRIGHT:231:          Illinois at Urbana-Champaign, nor the names of its
$ grep -nHr Illinois /tmp/xyz   

• http://llvm.org/docs/DeveloperPolicy.html#license

All of the code in LLVM is available under the University of Illinois/NCSA Open Source License, which boils down to this:

...

• You must retain the copyright notice if you redistribute LLVM.

I'm actually considering to add a new option --license to rustc and rustdoc so that they can always reproduce the content of the COPYING file. How does it sound?

[steveklabnik]

This is sort of a dup of #17690

[nodakai]

@steveklabnik Exactly! How did I overlook it???