Refer to rgbds' own install instructions

INSTALL.md

@@ -9,6 +9,12 @@ If you run into trouble, ask for help on IRC or Discord (see [README.md](README.
 
 Download and install [**Windows Subsystem for Linux**](https://docs.microsoft.com/en-us/windows/wsl/install-win10). Then open the **WSL terminal**.
 
+Update WSL's software before continuing. If you chose Debian, Ubuntu, or another distribution that uses `apt-get`, then enter this command:
+
+```bash
+apt-get update && apt-get upgrade
+```
+
 WSL has its own file system that's not accessible from Windows, but Windows files *are* accessible from WSL. So you're going to want to install pokecrystal within Windows. You'll have to change the **current working directory** every time you open WSL.
 
 For example, if you want to store pokecrystal in **C:\Users\\*\<user>*\Desktop**, enter this command:
@@ -36,9 +42,9 @@ Run setup and leave the default settings. At the "**Select Packages**" step, cho
 
 Double click on the text that says "**Skip**" next to each package to select the most recent version to install.
 
-Then download [**rgbds**](https://github.com/gbdev/rgbds/releases/): the latest **win64.zip** or **win32.zip** release. Extract it and put all the `exe` and `dll` files individually in **C:\cygwin64\usr\local\bin**.
+Then follow the [**rgbds** instructions](https://rgbds.gbdev.io/install/windows) for Windows with Cygwin to install **rgbds 0.4.1**.
 
-**Note: If you already have an older rgbds, you will need to update to 0.4.1.** Ignore this if you have never installed rgbds before. If a version newer than 0.4.1 does not work, try downloading 0.4.1.
+**Note:** If you already have an older rgbds, you will need to update to 0.4.1. Ignore this if you have never installed rgbds before. If a version newer than 0.4.1 does not work, try downloading 0.4.1.
 
 Now open the **Cygwin terminal** and enter the following commands.
 
@@ -59,13 +65,9 @@ Now you're ready to [build **pokecrystal**](#build-pokecrystal).
 
 Install [**Homebrew**](https://brew.sh/). Follow the official instructions.
 
-Open **Terminal** and enter the following commands.
+Open **Terminal** and prepare to enter commands.
 
-To install **rgbds**:
+Then follow the [**rgbds** instructions](https://rgbds.gbdev.io/install/macos) for macOS to install **rgbds 0.4.1**.
-
-```bash
-brew install rgbds
-```
 
 Now you're ready to [build **pokecrystal**](#build-pokecrystal).
 
@@ -82,13 +84,7 @@ To install the software required for **pokecrystal**:
 sudo apt-get install make gcc git
 ```
 
-To install **rgbds**:
+Then follow the [**rgbds** instructions](https://rgbds.gbdev.io/install/source) to build **rgbds 0.4.1** from source.
-
-```bash
-sudo apt-get install pkg-config flex bison libpng-dev
-git clone -b v0.4.1 --depth=1 https://github.com/gbdev/rgbds
-sudo make -C rgbds install
-```
 
 ### OpenSUSE
 
@@ -98,13 +94,7 @@ To install the software required for **pokecrystal**:
 sudo zypper install make gcc git
 ```
 
-To install **rgbds**:
+Then follow the [**rgbds** instructions](https://rgbds.gbdev.io/install/source) to build **rgbds 0.4.1** from source.
-
-```bash
-sudo zypper install pkg-config flex bison libpng16-devel
-git clone -b v0.4.1 --depth=1 https://github.com/gbdev/rgbds
-sudo make -C rgbds install
-```
 
 ### Arch Linux
 
@@ -114,13 +104,9 @@ To install the software required for **pokecrystal**:
 sudo pacman -S make gcc git rgbds
 ```
 
-If you want to compile and install **rgbds** manually instead of using the Arch package:
+Then follow the [**rgbds** instructions](https://rgbds.gbdev.io/install/arch) for Arch Linux to install **rgbds 0.4.1**.
 
-```bash
+If you want to compile and install **rgbds** yourself instead, then follow the [**rgbds** instructions](https://rgbds.gbdev.io/install/source) to build **rgbds 0.4.1** from source.
-sudo pacman -S pkg-config flex bison libpng
-git clone -b v0.4.1 --depth=1 https://github.com/gbdev/rgbds
-sudo make -C rgbds install
-```
 
 ### Termux
 
@@ -136,6 +122,8 @@ To install **rgbds**:
 sudo apt install rgbds
 ```
 
+If you want to compile and install **rgbds** yourself instead, then follow the [**rgbds** instructions](https://rgbds.gbdev.io/install/source) to build **rgbds 0.4.1** from source.
+
 ### Other distros
 
 If your distro is not listed here, try to find the required software in its repositories:
@@ -145,19 +133,7 @@ If your distro is not listed here, try to find the required software in its repo
 - `git`
 - `rgbds`
 
-If `rgbds` is not available, you'll also need these:
+If `rgbds` is not available, you'll need to follow the [**rgbds** instructions](https://rgbds.gbdev.io/install/source) to build **rgbds 0.4.1** from source.
-
-- `pkg-config`
-- `flex`
-- `bison`
-- `libpng` (and the development headers)
-
-To install **rgbds**:
-
-```bash
-git clone -b v0.4.1 --depth=1 https://github.com/gbdev/rgbds
-sudo make -C rgbds install
-```
 
 Now you're ready to [build **pokecrystal**](#build-pokecrystal).