libsdl: expand PACKAGECONFIG and enable native builds
Use PACKAGECONFIG instead of using logic in DEPENDS and EXTRA_OECONF, adding new
options for PulseAudio, tslib, DirectFB, OpenGL and X11. Pass
--disable-x11-shared so that it links to the X libraries instead of using
dlopen().
Disable tslib by default as the kernel event input subsystem is generally used.
SDL's OpenGL support requires X11 so check for both x11 and opengl, and merge
the dependencies.
Finally enable native builds, with a minimal PACKAGECONFIG that will build from
oe-core for native and nativesdk.
Signed-off-by: Ross Burton <ross.burton@intel.com>
