meson: add spirv-tools option to disable the optional dependency

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36689>

meson.build

@@ -1862,9 +1862,12 @@ else
   dep_llvmspirvlib = null_dep
 endif
 
+with_spirv_tools = get_option('spirv-tools') \
+    .enable_if(with_clc, error_message : 'CLC requires SPIRV-Tools')
+
 dep_spirv_tools = dependency(
   'SPIRV-Tools',
-  required : with_clc,
+  required : with_spirv_tools,
   version : '>= 2024.1'
 )
 if dep_spirv_tools.found()

meson.options

@@ -851,3 +851,9 @@ option(
   value : false,
   description : 'Build virtgpu_kumquat (only useful with gfxstream currently)'
 )
+
+option(
+  'spirv-tools',
+  type : 'feature',
+  description : 'Use SPIRV-Tools for dumping SPIR-V for debugging purposes (required by CLC)'
+)