chromium: prepare for M140

pkgs/applications/networking/browsers/chromium/common.nix

@@ -477,10 +477,17 @@ let
       # Rebased variant of patch to build M126+ with LLVM 17.
       # staging-next will bump LLVM to 18, so we will be able to drop this soon.
       ./patches/chromium-126-llvm-17.patch
+    ]
+    ++ lib.optionals (!chromiumVersionAtLeast "140") [
       # Partial revert of https://github.com/chromium/chromium/commit/3687976b0c6d36cf4157419a24a39f6770098d61
       # allowing us to use our rustc and our clang.
       ./patches/chromium-129-rust.patch
     ]
+    ++ lib.optionals (chromiumVersionAtLeast "140") [
+      # Rebased variant of the patch above due to
+      # https://chromium-review.googlesource.com/c/chromium/src/+/6665907
+      ./patches/chromium-140-rust.patch
+    ]
     ++ lib.optionals (!ungoogled && !chromiumVersionAtLeast "136") [
       # Note: We since use LLVM v19.1+ on unstable *and* release-24.11 for all version and as such
       # no longer need this patch. We opt to arbitrarily limit it to versions prior to M136 just
@@ -547,21 +554,17 @@ let
     ];
 
     postPatch =
-      lib.optionalString (!isElectron)
-        # TODO: reuse mkGnFlags for this
-        (
-          if (chromiumVersionAtLeast "136") then
-            ''
-              cp ${./files/gclient_args.gni} build/config/gclient_args.gni
-              chmod u+w build/config/gclient_args.gni
-              echo 'checkout_mutter = false' >> build/config/gclient_args.gni
-              echo 'checkout_glic_e2e_tests = false' >> build/config/gclient_args.gni
-            ''
-          else
-            ''
-              ln -s ${./files/gclient_args.gni} build/config/gclient_args.gni
-            ''
-        )
+      # TODO: reuse mkGnFlags for this
+      # TODO: reflow
+      lib.optionalString (!isElectron) ''
+        cp ${./files/gclient_args.gni} build/config/gclient_args.gni
+        chmod u+w build/config/gclient_args.gni
+        echo 'checkout_mutter = false' >> build/config/gclient_args.gni
+        echo 'checkout_glic_e2e_tests = false' >> build/config/gclient_args.gni
+      ''
+      + lib.optionalString (!isElectron && chromiumVersionAtLeast "140") ''
+        echo 'checkout_clusterfuzz_data = false' >> build/config/gclient_args.gni
+      ''
       + lib.optionalString (!isElectron) ''
 
         echo 'LASTCHANGE=${upstream-info.DEPS."src".rev}-refs/tags/${version}@{#0}' > build/util/LASTCHANGE

pkgs/applications/networking/browsers/chromium/patches/chromium-140-rust.patch

@@ -0,0 +1,21 @@
+diff --git a/build/config/compiler/BUILD.gn b/build/config/compiler/BUILD.gn
+index 77b02f76d2845fdf1a9429f704e59b8f7ab42993..e6ce3abe9872f415a9ef1cfc76f7267e7e44e1c9 100644
+--- a/build/config/compiler/BUILD.gn
++++ b/build/config/compiler/BUILD.gn
+@@ -1917,16 +1917,6 @@ config("runtime_library") {
+     configs += [ "//build/config/c++:runtime_library" ]
+   }
+ 
+-  # Rust and C++ both provide intrinsics for LLVM to call for math operations. We
+-  # want to use the C++ intrinsics, not the ones in the Rust compiler_builtins
+-  # library. The Rust symbols are marked as weak, so that they can be replaced by
+-  # the C++ symbols. This config ensures the C++ symbols exist and are strong in
+-  # order to cause that replacement to occur by explicitly linking in clang's
+-  # compiler-rt library.
+-  if (is_clang && !is_cronet_build) {
+-    configs += [ "//build/config/clang:compiler_builtins" ]
+-  }
+-
+   # TODO(crbug.com/40570904): Come up with a better name for is POSIX + Fuchsia
+   # configuration.
+   if (is_posix || is_fuchsia) {