[bazel] Fix v8_torque when imported in another workspace.

Signed-off-by: Piotr Sikora <piotrsikora@google.com>
Change-Id: I6caa36473b9fb92358e45b795f3f6ff39100586d
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3346680
Reviewed-by: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78500}

BUILD.bazel

@@ -80,11 +80,6 @@ load(":bazel/v8-non-pointer-compression.bzl", "v8_binary_non_pointer_compression
 # v8_enable_allocation_folding
 # v8_allocation_site_tracking
 
-v8_string(
-    name = "v8_root",
-    default = "third_party/v8/HEAD",
-)
-
 v8_flag(name = "v8_android_log_stdout")
 
 v8_flag(name = "v8_annotate_torque_ir")

bazel/defs.bzl

@@ -278,8 +278,10 @@ def v8_library(
         )
 
 def _torque_impl(ctx):
+    if ctx.workspace_name == "v8":
         v8root = "."
-    prefix = ctx.attr.prefix
+    else:
+        v8root = "external/v8"
 
     # Arguments
     args = []
@@ -331,7 +333,6 @@ _v8_torque = rule(
             cfg = "exec",
         ),
         "args": attr.string_list(),
-        "v8root": attr.label(default = ":v8_root"),
     },
 )