Add Arch Linux example to the README.md
There were examples of getting SDL2 development libraries on Ubuntu and Fedora. I've added an Arch Linux example.
@@ -48,6 +48,10 @@ Ubuntu example:
Fedora example:
> sudo dnf install SDL2-devel
+Arch example:
+(Arch doesn't have separate regular and development packages, everything goes together.)
+> sudo pacman -S sdl2
+
You might also need a C compiler (`gcc`).
### Mac OS X
