tagets/nine: convert to static/shared pipe-driver

...and as any other target (according to configure.ac) default to
static one. Why - the shared pipe-drivers bare unstable API/ABI and
can cause additional problems.

v2: Silence compiler warning.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
configure: correctly handle nine driver 'requirements'

In order to have a working nine target, one needs gallium swrast and at
least one other driver. Bail out at configure time if things are not
correctly setup to prevent further issues.

Cleanup the HAVE_GALLIUM_SOFTPIPE conditional.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
configure: do not mandate dri3 when building nine

Strictly speaking it has no requirement of dri3, additionally the original
code enforces dri3 enabled libGL to people who may not want and/or need it.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
configure: remove unused variables GALLIUM_{TARGET,STATE_TRACKERS}_DIRS

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
configure: drop DLOPEN_LIBS from GALLIUM_PIPE_DRIVER_LIBS

The former is already handled/added where needed.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
st/nine: use makefile.sources

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
targets/nine: cleanup the makefile

Lots to small changes all over with most significant ones:
 - Sort and cleanup the includes
 - Use AM_CPPFLAGS for the defines
 - Add the linker garbage collector
 - Restrict the exported symbols (think llvm)

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
targets/nine: make the target unversioned module

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>