Verify that rgbds is at least verson 0.4.0

Adapt the INSTALL guide from pokecrystal.

3 files changed, 174 insertions, 39 deletions

diff --git a/INSTALL.md b/INSTALL.md
index c708a013..48b0fa7c 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -1,60 +1,180 @@
-# Linux
+# Instructions
 
-	sudo apt-get install make git gcc
+These instructions explain how to set up the tools required to build **pokered**, including [**rgbds**](https://github.com/rednex/rgbds), which assembles the source files into a ROM.
 
-	sudo apt-get install byacc flex pkg-config libpng-dev
-	git clone https://github.com/rednex/rgbds
-	cd rgbds
-	sudo make install
-	cd ..
+If you run into trouble, ask for help on IRC or Discord (see [README.md](README.md)).
 
-	git clone https://github.com/pret/pokered
-	cd pokered
 
-To build **pokered.gbc** and **pokeblue.gbc**:
+## Windows 10
 
-	make
+Download and install [**Windows Subsystem for Linux**](https://docs.microsoft.com/en-us/windows/wsl/install-win10). Then open the **WSL terminal**.
 
-To build them individually:
+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 pokered within Windows. You'll have to change the **current working directory** every time you open WSL.
 
-	make red
-	make blue
+For example, if you want to store pokered in **C:\Users\\*\<user>*\Desktop**, enter this command:
 
+```bash
+cd /mnt/c/Users/<user>/Desktop
+```
 
-# Mac
+(The Windows `C:\` drive is called `/mnt/c/` in WSL. Replace *\<user>* in the example path with your username.)
 
-Get [**Homebrew**](http://brew.sh/).
+Then follow [the instructions for **Linux**](#linux).
 
-Then in **Terminal**, run:
+If this doesn't work, try following [the regular Windows instructions](#windows) below.
 
-	xcode-select --install
-	brew install rgbds
 
-	git clone https://github.com/pret/pokered
-	cd pokered
+## Windows
 
-To build **pokered.gbc** and **pokeblue.gbc**:
+Download [**Cygwin**](http://cygwin.com/install.html): **setup-x86_64.exe** for 64-bit Windows, **setup-x86.exe** for 32-bit.
 
-	make
+Run setup and leave the default settings. At the "**Select Packages**" step, choose to install the following, all of which are in the "**Devel**" category:
 
+- `make`
+- `git`
+- `gcc-core`
 
-# Windows
+Double click on the text that says "**Skip**" next to each package to select the most recent version to install.
 
-Download [**Cygwin**](http://cygwin.com/install.html): **setup-x86_64.exe** for 64-bit Windows, **setup-x86.exe** for 32-bit.
+Then download [**rgbds**](https://github.com/rednex/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**.
+
+**Note: If you already have an older rgbds, you will need to update to 0.4.0.** Ignore this if you have never installed rgbds before. If a version newer than 0.4.0 does not work, try downloading 0.4.0.
+
+Now open the **Cygwin terminal** and enter the following commands.
+
+Cygwin has its own file system that's within Windows, at **C:\cygwin64\home\\*\<user>***. If you don't want to store pokered there, you'll have to change the **current working directory** every time you open Cygwin.
+
+For example, if you want to store pokered in **C:\Users\\*\<user>*\Desktop**:
+
+```bash
+cd /cygdrive/c/Users/<user>/Desktop
+```
+
+(The Windows `C:\` drive is called `/cygdrive/c/` in Cygwin. Replace *\<user>* in the example path with your username.)
+
+Now you're ready to [build **pokered**](#build-pokered).
+
+
+## Mac OS X
+
+Install [**Homebrew**](https://brew.sh/). Follow the official instructions.
+
+Open **Terminal** and enter the following commands.
+
+To install **rgbds**:
+
+```bash
+brew install rgbds
+```
+
+Now you're ready to [build **pokered**](#build-pokered).
+
+
+## Linux
+
+Open **Terminal** and enter the following commands, depending on which distro you're using.
+
+### Debian or Ubuntu
+
+To install the software required for **pokered**:
+
+```bash
+sudo apt-get install make gcc git
+```
 
-Run setup and leave the default settings. At "Select Packages", choose to install the following:
+To install **rgbds**:
+
+```bash
+sudo apt-get install pkg-config flex bison libpng-dev
+git clone -b v0.4.0 --depth=1 https://github.com/rednex/rgbds
+sudo make -C rgbds install
+```
+
+### OpenSUSE
+
+To install the software required for **pokered**:
+
+```bash
+sudo zypper install make gcc git
+```
+
+To install **rgbds**:
+
+```bash
+sudo zypper install pkg-config flex bison libpng16-devel
+git clone -b v0.4.0 --depth=1 https://github.com/rednex/rgbds
+sudo make -C rgbds install
+```
+
+### Arch Linux
+
+To install the software required for **pokered**:
+
+```bash
+sudo pacman -S make gcc git
+```
+
+**rgbds** is available on the [AUR](https://aur.archlinux.org/packages/rgbds/).
+
+Alternatively, to install **rgbds** manually:
+
+```bash
+sudo pacman -S pkg-config flex bison libpng
+git clone -b v0.4.0 --depth=1 https://github.com/rednex/rgbds
+sudo make -C rgbds install
+```
+
+### Termux
+
+To install the software required for **pokered**:
+
+```bash
+sudo apt install make clang git sed
+```
+
+To install **rgbds**:
+
+```bash
+sudo apt install rgbds
+```
+
+### Other distros
+
+If your distro is not listed here, try to find the required software in its repositories:
 
 - `make`
+- `gcc` (or `clang`)
 - `git`
-- `gcc-core`
+- `rgbds`
+
+If `rgbds` is not available, you'll also need these:
+
+- `pkg-config`
+- `flex`
+- `bison`
+- `libpng` (and the development headers)
+
+To install **rgbds**:
+
+```bash
+git clone -b v0.4.0 --depth=1 https://github.com/rednex/rgbds
+sudo make -C rgbds install
+```
+
+Now you're ready to [build **pokered**](#build-pokered).
+
 
-Then download [**rgbds**](https://github.com/rednex/rgbds/releases/): the latest **win64.tar.gz** or **win32.tar.gz** release. Extract it and put all the `exe` and `dll` files individually in **C:\cygwin64\usr\local\bin**.
+## Build pokered
 
-In the **Cygwin terminal**, enter these commands:
+To download the **pokered** source files:
 
-	git clone https://github.com/pret/pokered
-	cd pokered
+```bash
+git clone https://github.com/pret/pokered
+cd pokered
+```
 
 To build **pokered.gbc** and **pokeblue.gbc**:
 
-	make
+```bash
+make
+```
diff --git a/Makefile b/Makefile
index 684d665e..3e2a6e89 100644
--- a/Makefile
+++ b/Makefile
@@ -38,19 +38,19 @@ all: $(roms)
 red:  pokered.gbc
 blue: pokeblue.gbc
 
-# For contributors to make sure a change didn't affect the contents of the rom.
-compare: $(roms)
-	@$(MD5) roms.md5
-
 clean:
-	rm -f $(roms) $(pokered_obj) $(pokeblue_obj) $(roms:.gbc=.map) $(roms:.gbc=.sym)
+	rm -f $(roms) $(pokered_obj) $(pokeblue_obj) $(roms:.gbc=.map) $(roms:.gbc=.sym) rgbdscheck.o
 	find gfx \( -iname '*.1bpp' -o -iname '*.2bpp' -o -iname '*.pic' \) -delete
 	$(MAKE) clean -C tools/
 
 tidy:
-	rm -f $(roms) $(pokered_obj) $(pokeblue_obj) $(roms:.gbc=.map) $(roms:.gbc=.sym)
+	rm -f $(roms) $(pokered_obj) $(pokeblue_obj) $(roms:.gbc=.map) $(roms:.gbc=.sym) rgbdscheck.o
 	$(MAKE) clean -C tools/
 
+# For contributors to make sure a change didn't affect the original contents of the ROMs.
+compare: $(roms)
+	@$(MD5) roms.md5
+
 tools:
 	$(MAKE) -C tools/
 
@@ -64,11 +64,14 @@ endif
 $(pokered_obj):  RGBASMFLAGS += -D _RED
 $(pokeblue_obj): RGBASMFLAGS += -D _BLUE
 
+rgbdscheck.o: rgbdscheck.asm
+	$(RGBASM) -o $@ $<
+
 # The dep rules have to be explicit or else missing files won't be reported.
 # As a side effect, they're evaluated immediately instead of when the rule is invoked.
 # It doesn't look like $(shell) can be deferred so there might not be a better way.
 define DEP
-$1: $2 $$(shell tools/scan_includes $2)
+$1: $2 $$(shell tools/scan_includes $2) | rgbdscheck.o
 	$$(RGBASM) $$(RGBASMFLAGS) -o $$@ $$<
 endef
 
diff --git a/rgbdscheck.asm b/rgbdscheck.asm
new file mode 100644
index 00000000..d10f8d50
--- /dev/null
+++ b/rgbdscheck.asm
@@ -0,0 +1,12 @@
+; pokered requires rgbds 0.4.0 or newer.
+MAJOR EQU 0
+MINOR EQU 4
+PATCH EQU 0
+
+if !DEF(__RGBDS_MAJOR__) || !DEF(__RGBDS_MINOR__) || !DEF(__RGBDS_PATCH__)
+	fail "pokered requires rgbds {MAJOR}.{MINOR}.{PATCH} or newer."
+elif (__RGBDS_MAJOR__ < MAJOR) || \
+	(__RGBDS_MAJOR__ == MAJOR && __RGBDS_MINOR__ < MINOR) || \
+	(__RGBDS_MAJOR__ == MAJOR && __RGBDS_MINOR__ == MINOR && __RGBDS_PATCH__ < PATCH)
+	fail "pokered requires rgbds {MAJOR}.{MINOR}.{PATCH} or newer."
+endc