Create a libweston-0.so

This commit also adds a libweston-0.pc file. The -0 is the abi version
introduced in the previous patch.

Signed-off-by: Giulio Camuffo <giuliocamuffo@gmail.com>
Reviewed-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
diff --git a/src/weston.pc.in b/src/weston.pc.in
index f2ffc9e..09e8580 100644
--- a/src/weston.pc.in
+++ b/src/weston.pc.in
@@ -8,5 +8,5 @@
 Name: Weston Plugin API
 Description: Header files for Weston plugin development
 Version: @WESTON_VERSION@
-Requires.private: wayland-server pixman-1 xkbcommon
-Cflags: -I${includedir}/weston -I{includedir}/libweston-@LIBWESTON_ABI_VERSION@
+Requires.private: libweston-@LIBWESTON_ABI_VERSION@
+Cflags: -I${includedir}/weston