Fix libunwind linked by default on x86_64 cpu when building via bazel (#2973)

* Fix libunwind linked by default on x86_64 cpu when build with bazel

* fix errors in getting_started.md english version

* add link libunwind instruction for bazel

Author: tongke6

BUILD.bazel

@@ -51,7 +51,7 @@ COPTS = [
     "//bazel/config:brpc_with_debug_lock": ["-DBRPC_DEBUG_LOCK=1"],
     "//conditions:default": ["-DBRPC_DEBUG_LOCK=0"],
 }) + select({
-    "@platforms//cpu:x86_64": ["-DBRPC_BTHREAD_TRACER"],
+    "//bazel/config:brpc_with_bthread_tracer": ["-DBRPC_BTHREAD_TRACER"],
     "//conditions:default": [],
 }) + select({
     "//bazel/config:brpc_with_asan": ["-fsanitize=address"],
@@ -412,7 +412,7 @@ cc_library(
         ":butil",
         ":bvar",
     ] + select({
-        "@platforms//cpu:x86_64": ["@com_github_libunwind_libunwind//:libunwind"],
+        "//bazel/config:brpc_with_bthread_tracer": ["@com_github_libunwind_libunwind//:libunwind"],
         "//conditions:default": [],
     }),
 )

bazel/config/BUILD.bazel

@@ -126,4 +126,14 @@ config_setting(
     name = "brpc_with_asan",
     define_values = {"with_asan": "true"},
     visibility = ["//visibility:public"],
+)
+
+config_setting(
+    name = "brpc_with_bthread_tracer",
+    constraint_values = [
+        "@platforms//cpu:x86_64",
+    ],
+    define_values = {
+        "with_bthread_tracer": "true",
+    },
 )

docs/cn/getting_started.md

@@ -392,7 +392,7 @@ brpc会自动检测valgrind（然后注册bthread的栈）。不支持老版本
 
 ## libunwind: 1.3-1.8.1
 
-bRPC默认**不**链接 [libunwind](https://github.com/libunwind/libunwind)。用户需要追踪bthread功能则链接libunwind，可以给config_brpc.sh增加`--with-bthread-tracer`选项或者给cmake增加`-DWITH_BTHREAD_TRACER=ON`选项。
+bRPC默认**不**链接 [libunwind](https://github.com/libunwind/libunwind)。用户需要追踪bthread功能则链接libunwind，可以给config_brpc.sh增加`--with-bthread-tracer`选项或者给cmake增加`-DWITH_BTHREAD_TRACER=ON`选项，如果是用 bazel 构建，请添加 `--define with_bthread_tracer=true` 选项。
 
 建议使用最新版本的libunwind。
 

docs/en/getting_started.md

@@ -385,7 +385,7 @@ brpc detects valgrind automatically (and registers stacks of bthread). Older val
 
 ## libunwind: 1.3-1.8.1
 
-brpc does **not** link [libunwind](https://github.com/libunwind/libunwind) by default. Users link libunwind on-demand by adding `--with-glog` to config_brpc.sh or adding `-DWITH_GLOG=ON` to cmake.
+brpc does **not** link [libunwind](https://github.com/libunwind/libunwind) by default. Users link libunwind on-demand by adding `--with-bthread-tracer` to config_brpc.sh or adding `-DWITH_BTHREAD_TRACER=ON` to cmake, if building with Bazel, please add the `--define with_bthread_tracer=true` option.
 
 It is recommended to use the latest possible version of libunwind.