1. Make the vcpkg hack minimal by only defining the options it needs
before `include(Platforms)`.
Every dependent option needed by vcpkg has to be recalculated
after `include(Platforms)`. This brings the count of such options
down to 1 (`PACKET_ENCRYPTION`).
2. `include(Platforms)` before the rest of the options.
3. Group related options together into sections and add comments.
4. Fix `--gc-sections` for C files. Also adds `-Wl,--as-needed`.
Note: `PIE` can now be `ON` even if `BUILD_TESTING` is `OFF`.
1. Platform and toolchain files are now all under `platforms/`, with a
single `CMake/platforms/${platform}.cmake` per platform.
2. Custom functions/macros are under `functions/`.
3. Finder modules are in `/finders`.
Gleb Mazovetskiy