The LLVM Coding Standards [1] discourages the use of 'else' or 'else if'
after something that interrupts control flow. Bulk fix all instances as
I'm working on this part of LLDB.

[1] https://llvm.org/docs/CodingStandards.html#don-t-use-else-after-a-return

This commit adds colour settings to the list of breakpoints in order to
grey out breakpoints that have been disabled.

Replace (questionable) header globs with an explicit argument supported
by llvm_add_library.

This patch should be mostly obvious, but in one place, this patch
changes:

  const auto &it = std::find(...)

to:

  auto it = llvm::find(...)

We do not need to bind to a temporary with const ref.

If we're not touching them, we don't need to do anything special to pass
them along -- with one important caveat: due to how cmake arguments
work, the implicitly passed arguments need to be specified before
arguments that we handle.

This isn't particularly nice, but the alternative is enumerating all
arguments that can be used by llvm_add_library and the macros it calls
(it also relies on implicit passing of some arguments to
llvm_process_sources).

This patch replaces a local implementation of bit_ceil with
llvm::bit_ceil.  Technically, the local implementation evaluates to 0
on input 0, whereas llvm::bit_ceil evaluates to 1, but that doesn't
matter because we have:

  // Can't watch zero bytes.
  if (user_size == 0)
    return {};

This allows languages to make decisions based on the whole set of symbol
contexts, giving them strictly more power than when they are only
allowed to see one at a time.

Make StreamAsynchronousIO an unique_ptr instead of a shared_ptr. I tried
passing the class by value, but the llvm::raw_ostream forwarder stored
in the Stream parent class isn't movable and I don't think it's worth
changing that. Additionally, there's a few places that expect a
StreamSP, which are easily created from a StreamUP.