OpenGL headers not required for compilation

docs/compile.dox

@@ -87,10 +87,10 @@ Once you have Xcode installed, move on to @ref compile_generate.
 
 @subsubsection compile_deps_x11 Dependencies for Linux and X11
 
-To compile GLFW for X11, you need to have the X11 and OpenGL header packages
-installed, as well as the basic development tools like GCC and make.  For
-example, on Ubuntu and other distributions based on Debian GNU/Linux, you need
-to install the `xorg-dev` package, which pulls in all X.org header packages.
+To compile GLFW for X11, you need to have the X11 packages installed, as well as
+the basic development tools like GCC and make.  For example, on Ubuntu and other
+distributions based on Debian GNU/Linux, you need to install the `xorg-dev`
+package, which pulls in all X.org header packages.
 
 Once you have installed the necessary packages, move on to @ref
 compile_generate.