[libclc] Fix llvm-spirv dependency when llvm-spirv is built in-tree (#188896)

When SPIRV-LLVM-Translator is built in-tree (i.e., placed in
llvm/projects folder), llvm-spirv target exists.

Drop legacy llvm-spirv_target dependency (was for non-runtime build) and
add llvm-spirv to runtimes dependencies.

libclc/CMakeLists.txt

@@ -94,7 +94,6 @@ if( NOT LIBCLC_USE_SPIRV_BACKEND )
   else()
     find_program( LLVM_SPIRV llvm-spirv HINTS ${LLVM_TOOLS_BINARY_DIR} )
     set( llvm-spirv_exe "${LLVM_SPIRV}" )
-    set( llvm-spirv_target )
   endif()
 endif()
 

libclc/cmake/modules/AddLibclc.cmake

@@ -127,7 +127,7 @@ function(link_libclc_builtin_library target_name)
                 --spirv-max-version=1.1
                 --spirv-ext=+SPV_KHR_fma
                 -o ${builtins_lib} ${linked_bc}
-        DEPENDS ${llvm-spirv_target} ${linked_bc}
+        DEPENDS ${linked_bc}
       )
     endif()
   else()

llvm/runtimes/CMakeLists.txt

@@ -554,7 +554,7 @@ if(build_runtimes)
 
   # TODO: We need to consider passing it as '-DRUNTIMES_x86_64_LLVM_ENABLE_RUNTIMES'.
   if("libclc" IN_LIST LLVM_ENABLE_RUNTIMES)
-    foreach(dep clang llvm-link opt llvm-ar llvm-ranlib)
+    foreach(dep clang llvm-link opt llvm-ar llvm-ranlib llvm-spirv)
       if(TARGET ${dep})
         list(APPEND extra_deps ${dep})
       endif()