Cross-compiling SDL for the Ubuntu Phone is possible, and fairly simple.

1) Install the Ubuntu SDK

2) Create a development chroot:
	$ sudo click chroot -a armhf -f ubuntu-sdk-14.10 create

3) Obtain the SDL sources from mercurial or a tarball. The sources for the
   supplied SDL build are included in this repo and were obtained from
   mercurial on 2015-05-22.

4) Log in to your chroot as root. You will have to be root to install
   packages, as you cannot use "sudo" in the chroot by default. The installed
   packages will be lost when you log out of the chroot, and the chroot will
   return to a pristine state. If you wish to keep the changes, log in with
   "maint" instead of "run":
	$ sudo click chroot -a armhf -f ubuntu-sdk-14.10 run

5) Install the minimal dependencies for SDL:
	# apt-get install libxkbcommon-dev:armhf libdbus-1-dev:armhf

6) Drop priveleges - don't build as root!
	# su your_username

7) Create a build directory and change to it:
	$ mkdir SDL2-2.0.4/build && cd SDL2-2.0.4/build

8) Configure the build, disabling broken or unneeded components. Building with
   debugging symbols and no optimisation will help us all:
	$ PKG_CONFIG_PATH=/usr/lib/arm-linux-gnueabihf/pkgconfig/ \
	  ../configure --host=arm-linux-gnueabihf CFLAGS="-g -O0" \
	  --disable-mir-shared --disable-video-opengl \
	  --disable-video-wayland --disable-video-x11 --prefix=/tmp/mysdlbuild

9) Build:
	$ make && make install

The libraries will be installed in /tmp/mysdlbuild/lib/ and can be copied into
the template lib/armhf directory.

TODO: this builds a very minimal SDL. Please experiment with additional audio
drivers etc and feed back whether they work. Thanks.