Add kill switch for unsupported clangd flags: updated patch for clangd v21

Original License: GPL-2.0-or-later - https://spdx.org/licenses/GPL-2.0-or-later.html

License: GPL-3.0-only - https://spdx.org/licenses/GPL-3.0-only.html

---

 build/config/compiler/BUILD.gn | 11 ++++++++++-

 build/config/compiler/BUILD.gn | 14 +++++++++++---

 build_overrides/build.gni      |  3 +++

 2 files changed, 13 insertions(+), 1 deletion(-)

 2 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn

--- a/build/config/compiler/BUILD.gn

+++ b/build/config/compiler/BUILD.gn

@@ -634,7 +634,7 @@ config("compiler") {

     # TODO(crbug.com/413427035): Remove once

     # https://github.com/llvm/llvm-project/pull/136867/ is landed.

-    if (!is_win && !llvm_android_mainline &&

+    if (!is_win && !llvm_android_mainline && !skip_clangd_unsupported_options &&

         default_toolchain != "//build/toolchain/cros:target") {

       cflags += [ "-fextend-variable-liveness=none" ]

     }

@@ -1728,7 +1728,7 @@ config("clang_revision") {

 config("clang_warning_suppression") {

   # Some build configs use older versions of clang that don't support WSMs

   if (!is_nacl && default_toolchain != "//build/toolchain/cros:target" &&

-      !llvm_android_mainline && is_clang &&

+      !llvm_android_mainline && is_clang && !skip_clangd_unsupported_options &&

       clang_warning_suppression_file != "") {

     from_build_root =

         rebase_path(clang_warning_suppression_file, root_build_dir)

@@ -2065,7 +2065,6 @@ config("default_warnings") {

         # TODO(crbug.com/376641662): Fix and re-enable.

         "-Wno-nontrivial-memcall",

       cflags_cc += [

         # TODO(crbug.com/328490295): Fix and re-enable for C flags.

         "-Wenum-compare-conditional",

@@ -2091,6 +2090,16 @@ config("default_warnings") {

       # other issues if the versions are incompatible.

       cflags += [ "-Wno-version-check" ]

       ldflags += [ "-Wno-version-check" ]

@@ -2104,6 +2103,15 @@ config("default_warnings") {

       ]

     }

+    if (skip_clangd_unsupported_options) {

+      cflags -= [

+        "-Wno-thread-safety-reference-return",

+        "-Wno-nontrivial-memcall",

+      ]

+      cflags_cc -= [

+          "-Wno-c++11-narrowing-const-reference",

+          "-Wno-missing-template-arg-list-after-template-kw",

+      ]

+    }

     }

     # Some builders, such as Cronet, use a different version of Clang than

+

     # Disable the GNU line marker warning when building a target with Icecc,

     # ccache, or both. This warning appears frequently when compiling

     # files that use GNU-style line markers with Clang and Icecc. It can

diff --git a/build_overrides/build.gni b/build_overrides/build.gni

--- a/build_overrides/build.gni

+++ b/build_overrides/build.gni