[gn] port 48e5f70 (no more LLVM_HAVE_LIBXAR in ld64.lld)

Author: nico

llvm/utils/gn/secondary/lld/test/BUILD.gn

@@ -1,6 +1,5 @@
 import("//llvm/lib/DebugInfo/PDB/enable_dia.gni")
 import("//llvm/triples.gni")
-import("//llvm/utils/gn/build/libs/xar/enable.gni")
 import("//llvm/utils/gn/build/libs/xml/enable.gni")
 import("//llvm/utils/gn/build/libs/zlib/enable.gni")
 import("//llvm/utils/gn/build/write_cmake_config.gni")
@@ -66,12 +65,6 @@ write_cmake_config("lit_site_cfg") {
     values += [ "LLVM_ENABLE_DIA_SDK=0" ]  # Must be 0.
   }
 
-  if (llvm_enable_libxar) {
-    values += [ "LLVM_HAVE_LIBXAR=1" ]
-  } else {
-    values += [ "LLVM_HAVE_LIBXAR=0" ]  # Must be 0.
-  }
-
   if (llvm_enable_libxml2) {
     values += [ "LLVM_ENABLE_LIBXML2=1" ]
   } else {