Add packaging instructions to build instructions

Signed-off-by: Avery King <gperson@disroot.org>

BUILDING.md

@@ -377,25 +377,6 @@ Optionally, install Tenacity:
 cmake --install build
 ```
 
-### Linux: Building an AppImage
-
-**NOTE**: This is only supported on 64-bit x86. ARM and other architectures are
-currently unsupported.
-
-You can build an AppImage yourself. This requires that you have previously
-built Tenacity. There is no need to install Tenacity first.
-
-If you've used vcpkg in your build, you must set `VCPKG_LIB_PATH` to the
-directory vcpkg copied libraries too. Otherwise, there is no need to set it at
-all.
-
-**NOTE**: Ensure that you are correctly setting `VCPKG_LIB_PATH` by ensuring
-the directory exists and there are libraries in that folder. If the directory
-doesn't exist, required libraries won't get packaged.
-
-To build an AppImage, simply run `cpack` from the root of your build directory.
-The AppImage will be in the `package/` directory of the build folder.
-
 ## Build options
 
   * **VCPKG** (ON|OFF): whether to use dependencies from vcpkg. ON by default
@@ -469,3 +450,51 @@ export TENACITY_TRIPLET_OVERRIDE=x64-linux-dynamic
 Overriding triplets might be required in some cases. For example, using static
 builds of wxWidgets on Linux is not supported, but vcpkg builds static
 libraries by default. The `x64-linux-dynamic` triplet must be used instead.
+
+## Building Packages
+Building a package is extremely simple. Before starting, you must ensure all of
+Tenacity has been built and is up to date (i.e., nothing needs a recompile).
+Then, all you need to do is run the following command:
+
+```bash
+$ cpack /path/to/build/folder
+```
+
+All outputs are in the `package/` directory in your build folder. They will be
+one of the following:
+
+- An (Inno Setup) installer for Windows
+- A DMG for macOS, or
+- An AppImage for Linux
+
+Along with your package comes a JSON file and various `.sha256` files. The JSON
+files are simply unused artificats of the packaging process, while the
+`.sha256` files contain the SHA256 hashes of the packaging artifacts. They are
+automatically generated by CPack to save us a step when we build nightly and
+official release binaries. You can simply delete both of those files if you
+plan on only using these packages for yourself.
+
+While the packaging process is very simple, there are some advisories, which
+are listed below. It is _highly_ recommend that you read them so you are aware
+of potential issues you may encounter.
+
+### Inno Setup Installer Notes
+In previous versions of Tenacity, the installer was _not_ built by CPack and
+instead by its own target `innosetup`. This requires that you have previously
+built Tenacity. To build the installer, you must build that target.
+
+### AppImage Notes (Linux)
+Unfortunately, the AppImage is a bit finicky right now; it might not run on all
+distros, and some distros (notably Arch at the moment) may fail to build the
+AppImage successfully. At this time of writing, Rocky Linux 9 (or, presumably,
+any similar distro) can successfully build the AppImage.
+
+Only x86_64 is supported at the moment. We do not plan to support x86 but are
+interested in supporting aarch64. You are welcome to open a pull request to
+make this happen.
+
+If you are using vcpkg, you must set `VCPKG_LIB_PATH` to the directory in your
+build folder where vcpkg copied its libraries older. For example, this could be
+`/path/to/build/folder/vcpkg_installed/x64-linux-dynamic/lib`. Leaving this
+variable unset will cause the script to leave out vcpkg's libraries, which can
+cause issues.