spice: convert to meson

spice: convert to meson

Faster compilation.

Removed autotools patches.

Backported meson patch to fix compilation and pkgconfig file.

Before:

time make package/spice/compile -j 12
Executed in   62.85 secs   fish           external
   usr time   56.45 secs  276.00 micros   56.45 secs
   sys time    8.06 secs   46.00 micros    8.06 secs

Before + PKG_BUILD_PARALLEL:

Executed in   45.40 secs   fish           external
   usr time   63.08 secs  253.00 micros   63.08 secs
   sys time    8.57 secs   44.00 micros    8.57 secs

After:

time make package/spice/compile -j 12
Executed in   16.54 secs   fish           external
   usr time   41.29 secs  266.00 micros   41.29 secs
   sys time    4.76 secs   45.00 micros    4.76 secs

Signed-off-by: Rosen Penev <rosenp@gmail.com>