doc: Add Windows-specific notes

README.md

@@ -18,7 +18,9 @@ Immediate goals:
   - [x] decode and encode data
 
 
-## Project Setup Instructions
+## Working with the project
+
+WINDOWS USERS READ THIS: [Windows-specific notes](doc/windows.md)
 
 ### Prerequisites:
 

doc/windows.md

@@ -0,0 +1,47 @@
+# Notes for Windows Users
+
+FOSS-VG is focused on development on UNIX-like systems for UNIX-like systems.
+The development environment is built in a way that requires UNIX tools.
+
+There are two options to deal with this on Windows:
+
+1) Use Cygwin to get a UNIX-like environment on Windows.
+This is the option to choose if you want to develop FOSS-VG on Windows.
+Working on FOSS-VG on Cygwin is pretty much the same as on other
+operating systems with the exception that special care needs to be taken
+setting up the development environment.
+
+2) Use the `windows` branch.
+This is the option to use when just building on Windows.
+Might need some fixing up to actually work properly.
+Don't commit new code to that branch as it cannot be merged back into master.
+Merging from the `windows` branch into master would break master for all other
+operating systems.
+
+# Using Cygwin
+
+The build system has special provisions built-in to deal with the Windows-iness
+of Cygwin environments. But it still needs some specific setup to work properly.
+
+When getting the prerequisites set up, make sure to install CMake on Windows,
+NOT on Cygwin. CMake is used for dependencies that aren't easy to build
+on Cygwin, therefore they are built on Windows.
+
+You will also need MinGW tools on Windows that CMake can use to build the
+dependencies. In case they aren't in your PATH variable, you can use the
+`.localenv.bashrc` to automatically add them when loading the development
+environment like so:
+```sh
+PATH=$PATH:/cygdrive/c/path/to/your/mingw/bin
+```
+Note that the mingw tools are added to the end of the path variable so they
+don't override Cygwin's programs in regular use.
+
+# Using the `windows` Branch
+
+Good luck.
+
+It's currently not actively being maintained as only building FOSS-VG is not
+a task that is commonly needed.
+This will probably change when Windows-only builds have to be performed
+regularly.