Now that I am reading the README of Evas 1.7.4 (I would think only this lib deals with backend buffers), the restriction seems much less strict:
Must: libc eina (1.1.0 or better) freetype (2.1.9 or better)
Recommended: libX11 + libXext + libXrender OpenGL2.0 or OpenGL-ES 2.0 fontconfig libpng libjpeg (6.0 or better) eet (1.5.0 or better) fribidi harfbuzz liblinebreak
Optional: XCB SDL OpenGL esvg libtiff libgif edb DirectFB evas_generic_loaders
So X11 is optional.
Using configure with: The following seems interesting:
--enable-fb[=static] [well less interesting] this is the software framebuffer driving engine. this uses the linux framebuffer device (/dev/fb{X}) and will currently just inherit the current framebuffer settings on the fb device and use them to run in. this engine is almost fully functional except for the fb management itself. this engine is specifically geared towards people writing minimalist display systems for embedded devices such as the ipaq, zaurus, etc. it also scales up to high-res desktop systems as well.
--enable-directfb[=static] this is the direct fb engine that uses direcftb (http://www.directfb.org) on linux to access the framebuffer with (or maybe without) acceleration. for people making set-top boxes or just wanting an alternative to X this is really good. it may also be useful for embedded devices supported by directfb that offer acceleration (otherwise the fb driver will likely be faster). as such this engine is in relative disrepair and is not maintained. use with great care.
--enable-buffer[=static] this enables the memory buffer rendering engine. this engine renders to a region of memory that is considered to be a 32bit ARGB buffer of pixels, allowing the results of rendering to be directly read out or used again for other purposes.
--enable-software-sdl[=static] [probably the most interesting since SDL is ported to Genode] this is the sdl engine that uses sdl library (http://www.libsdl.org). This library should work on many operating system. the buffer is software-rendered with evas's default software rendering core.