Improvements to building CKW

* Always link Compute Kernel Writer statically to Compute Library

* Move CMake logic to be set on libckw target

* Build CKW in parallel from SCons

Resolves: COMPMID-6297

Change-Id: I247a1f6ddf84a58032358a196574866b857d9bdc
Signed-off-by: Jakub Sujak <jakub.sujak@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/9834
Reviewed-by: Viet-Hoa Do <viet-hoa.do@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>
Benchmark: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
diff --git a/SConscript b/SConscript
index c9a56ed..c713955 100644
--- a/SConscript
+++ b/SConscript
@@ -31,8 +31,12 @@
 import json
 import codecs
 
-print("DEPRECATION NOTICE: Legacy libarm_compute_core has been deprecated. Link your application only to "
-      "libarm_compute for core library functionality")
+from SCons.Warnings import warn, DeprecatedWarning
+
+warn(DeprecatedWarning,
+     "DEPRECATION NOTICE: Legacy libarm_compute_core has been deprecated and is scheduled for removal in 24.02 release."
+     " Link your application only to libarm_compute for core library functionality"
+     )
 
 VERSION = "v0.0-unreleased"
 LIBRARY_VERSION_MAJOR = 31
@@ -123,6 +127,9 @@
         cloned_build_env["LINKFLAGS"].remove('-pie')
         cloned_build_env["LINKFLAGS"].remove('-static-libstdc++')
 
+    if env['ckw']:
+        libs.append('libckw.a')
+
     if static:
         obj = cloned_build_env.StaticLibrary(name, source=sources, LIBS = arm_compute_env["LIBS"] + libs)
     else: