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>

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>

Supersedes openwrt/packages#10873

Ref: https://github.com/openwrt/packages/pull/10873
Reported-by: Rosen Penev <rosenp@gmail.com>
Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>

Fixes openwrt/packages#10451

Supersedes openwrt/packages#10461

Signed-off-by: Rosen Penev <rosenp@gmail.com>
(use separate upstreamed patches)
Ref: https://github.com/openwrt/packages/pull/10461
Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>