These are identified by misc-include-cleaner.  I've filtered out those
that break builds.  Also, I'm staying away from llvm-config.h,
config.h, and Compiler.h, which likely cause platform- or
compiler-specific build failures.

Fixes #83241

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Signed-off-by: Troy-Butler <squintik@outlook.com>
Co-authored-by: Troy-Butler <squintik@outlook.com>

* A lot of `tapi installapi` options are already shared with clang, but
not all. This patch handles installapi-specific options by filtering for
them in the initial argv input, then passing the rest to the clang
driver.
* Installapi not only generates a text file but also reports to library
developers when there are inconsistencies between an interface and its
implementation. To allow this, add support for reporting installapi
diagnostics. This will be leveraged in the verifier service.

A distinction that doesn't _usually_ matter is that the
MachO::SymbolKind is really a mapping of entries in TBD files not
symbols. To better understand this, rename the enum so it represents an
encoding mapped to TBDs as opposed to symbols alone.

For example, it can be a bit confusing that "GlobalSymbol" is a enum
value when all of those values can represent a GlobalSymbol.

This patch replaces uses of StringRef::{starts,ends}with with
StringRef::{starts,ends}_with for consistency with
std::{string,string_view}::{starts,ends}_with in C++20.

I'm planning to deprecate and eventually remove
StringRef::{starts,ends}with.

… format.

Formats >= TBDv4 will now encode new attribute that the system static
linker wil read when tbd files replace binary dylibs.

This change adds the PLATFORM XMACRO to simplify the addition of new MachO
platforms and reduce the number of required changes. Many of the changes needed
for adding a new platform are mechanical, such as adding new cases to a switch
statement. This will help streamline the process by consolidating much of the
necessary information into the MachO.def file.

Differential Revision: https://reviews.llvm.org/D139487

Both Swift & LLD use TextAPI reader/writer apis to interface with TBD
files. Add doc strings to document what each API does. Also, add
shortcut APIs for validating input is a TBD file.

This reduces the differences between downstream and how tapi calls into
these APIs.