This is a near complete rewrite of the shared library embedder/bundler
code. It now correctly resolves shared libraries that link to other
shared library files in the same package via use of `@path`, which the
libwebp package does extensively between `libwebpdemux.2.dylib`,
`libwebp.7.dylib` and `libsharpyuv.0.dylib`.
These relative shared library links were not understood at all by the
old library bundler code.
The new replacement here fully understands and resolves all
`@<something>` placeholders in links to shared libraries. It operates in
a two-step process where it first walks down the three of all shared
libraries that Emacs links to, and all that they link to, etc. building
a copy and relink plan.
In a second step it then executes the copy plan, followed by the
relinking plan.
The result is a fully self-contained Emacs.app binary, which has no
dependencies on Homebrew or anything installed via Homebrew. Builds have
been tested on a fresh install of macOS Sonoma VM, with nothing but
Xcode Command Line Tools installed. Everything from native compilation
to webp, svg, png rendering, and more worked as expected.
