protobuf-c: don't build shared host library

No point and can avoid rpath hacks.

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

libs/protobuf-c/Makefile

@@ -46,7 +46,7 @@ define Package/libprotobuf-c/description
 endef
 
 CMAKE_HOST_OPTIONS += \
-	-DBUILD_SHARED_LIBS=ON \
+	-DBUILD_SHARED_LIBS=OFF \
 	-DCMAKE_CXX_STANDARD=11 \
 	-DCMAKE_SKIP_RPATH=OFF \
 	-DCMAKE_INSTALL_RPATH="${STAGING_DIR_HOSTPKG}/lib"