delete clover

there comes a time when a project has to be declared unfit to remain
in the tree

this frontend hasn't seen actual development in about 6 years

if someone has a pressing need to continue development, there's no
blocker to un-deleting it, but unless that happens, there's now a
more featureful, more conformant, more active CL frontend in the tree

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Reviewed-by: Karol Herbst <kherbst@redhat.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19385>

include/meson.build

@@ -89,7 +89,7 @@ if with_gallium_st_nine
     subdir : 'd3dadapter',
   )
 endif
-
+ 
 opencl_headers = files(
   'CL/cl.h',
   'CL/cl.hpp',
@@ -113,11 +113,3 @@ opencl_headers = files(
   'CL/opencl.h',
   'CL/opencl.hpp',
 )
-# Only install the headers if we are building a stand alone implementation and
-# not an ICD enabled implementation
-if with_gallium_clover and not with_opencl_icd
-  install_headers(
-    opencl_headers,
-    subdir: 'CL'
-  )
-endif