Overhaul install instructions

src/pages/install/index.md

@@ -0,0 +1,107 @@
+
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+# Installing RGBDS
+
+Most people will want to use a release (the latest the bestest!), but if you are willing to help us test new features, you may consider [using a development version](/install/master).
+
+The two main options to install a release of RGBDS are to download pre-built executables, or to [build from source](/install/source).
+Below is a list of <abbr title="Operating System">OS</abbr>es for which we know pre-built executables are available.
+
+If your OS isn’t listed below, try finding `rgbds` in your package manager—refer to your OS' documentation for help.
+If you still can’t find RGBDS, or the specific version you are looking for is unavailable, you will have to [compile it from source](#building-from-source).
+
+<Tabs>
+<TabItem value="windows" label="Windows">
+
+The install instructions change a bit depending on the environment you wish to use RGBDS with.
+
+:::tip
+
+The "plain Windows" instructions may also work for some environments listed further below, since most of them pick up Windows' `PATH`.
+However, if you have such an environment, we recommend you follow its specific install instructions instead.
+
+:::
+
+<details>
+<summary>"Plain" Windows (CMD, PowerShell)</summary>
+
+1. First, [pick the version you want to install](/docs). If you want to [use `master`](/docs/master/#what) instead of a release, [go here](#using-rgbds-master).
+2. Follow the "release page" link below "GitHub links", and grab either of the `win32` (for 32-bit Windows) or `win64` (for 64-bit Windows) `.zip` files, near the bottom of the page.
+3. Unzip that file, you should get the `.exe` files alongside a couple of `.dll`s.
+4. Either:
+   - Put all of the files in a directory, then add it to the `PATH`.
+     This will permanently allow you to use RGBDS. If you only want to modify the PATH temporarily, instead of the permanent [`setx` command](https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/setx), you can use  the **temporary** [`set` one](https://docs.microsoft.com/en-us/windows-server/administration/windows-commands/set_1): <code>set PATH="%PATH%<var>&lt;rgbds_path&gt;</var></code> for `cmd.exe`.
+     Use one of the following methods:
+     - Graphically:
+       1. Open Control Panel
+       2. Click "User Accounts"
+       3. Click "User Accounts" again
+       4. Click "Change my environment variables"
+       5. Select the "Path" line in the **top** panel
+       6. Click "Edit..."
+       7. Click "Browse...", select the folder the files are in, and click OK
+       8. Make sure that the new entry (which should be highlighted) is at the bottom of the list; if not, click on "Move Down" until it is
+       9. Click "OK"
+       10. Click "OK"
+     - Using a command line:
+       1. Use Explorer to go into the folder the files are in (you should see `rgbasm.exe` etc.), and click a blank part of the address bar near the top. Copy this path, and **use this instead of <code><var>&lt;rgbds_path&gt;</var></code> in the third step!**
+       2. Open `cmd` or PowerShell
+       3. Type <code>setx PATH "%PATH%<var>&lt;rgbds_path&gt;</var>;"</code> for `cmd.exe`, or <code>setx PATH ${"{"}Env:PATH}<var>&lt;rgbds_path&gt;</var>;</code> for PowerShell; replace <code><var>&lt;rgbds_path&gt;</var></code> with the path you copied in the first step
+       4. Close the window for the changes to take effect
+   - Put all of the files in your project's directory
+   - Put all of the files in a directory already in the `PATH`
+5. Profit! RGBDS can now be used from your favorite command line (`cmd.exe` or PowerShell, most likely). You can test it by running `rgbasm --version`.
+
+</details>
+<details>
+<summary>Cygwin, MSYS2</summary>
+
+Follow steps 1 to 3 of the "plain Windows" instructions to get the release's files; then, copy all of the `.exe` and `.dll` files to the `/usr/local/bin` directory of Cygwin/MSYS2's installation.
+(You can get its equivalent Windows path by running `cygpath -w /usr/local/bin`.)
+**Do not put them in a subdirectory** (e.g. `/usr/local/bin/rgbds`)**!**
+This would not work.
+
+After that, you should be able to use RGBDS from within the Cygwin/MSYS2 terminal, which you can confirm by running `rgbasm -V`.
+If this doesn't work, check that `/usr/local/bin` is within the PATH there (`echo $PATH`); if it isn't, you must add it (e.g. `export PATH="/usr/local/bin:$PATH"` in the `~/.bashrc`).
+
+Note: if you can choose between using Cygwin or MSYS2, be advised that Cygwin is slower and has been reported to cause a bit of trouble to some.
+
+</details>
+<details>
+<summary>WSL, and all other Linux-like environments</summary>
+
+For these, you have to [build from source](/install/source).
+On WSL, the default package manager (to install any build prerequisites) is `apt-get` (example: `sudo apt-get install libpng-dev`).
+
+</details>
+
+</TabItem>
+<TabItem value="arch" label="Arch Linux">
+
+RGBDS is now available in the official repos as [`community/rgbds`](https://www.archlinux.org/packages/community/x86_64/rgbds/); you can also get the [latest master](/docs/master) via the [`rgbds-git`](https://aur.archlinux.org/packages/rgbds-git) AUR package, or RGBDS 0.2.5 from [`rgbds2`](https://aur.archlinux.org/packages/rgbds2), still from the AUR.
+
+```bash
+pacman -S rgbds
+```
+
+We refer you to the Arch Linux wiki on how to install [official packages](https://wiki.archlinux.org/index.php/Pacman#Installing_packages) or [AUR packages](https://wiki.archlinux.org/index.php/Arch_User_Repository#Installing_and_upgrading_packages), or to find and use an [AUR helper](https://wiki.archlinux.org/index.php/AUR_helpers).
+
+</TabItem>
+<TabItem value="macos" label="macOS">
+
+RGBDS is available on [Homebrew](https://brew.sh) as the [`rgbds` package](https://formulae.brew.sh/formula/rgbds).
+
+```bash
+brew install rgbds
+```
+
+You can also install the [`master` branch](/docs/master) by passing the `--HEAD` flag:
+
+```bash
+brew install rgbds --HEAD
+```
+
+</TabItem>
+</Tabs>