fix cross-compile

debian/patches/d-0005-clippy-feature-sync.patch

@@ -14,6 +14,15 @@ index e959c1a6511..39308996342 100644
  toml = "0.5.3"
  unicode-normalization = "0.1"
  semver = "0.11"
+@@ -29,7 +29,7 @@ rustc-semver = "1.1.0"
+ # see <https://github.com/rust-lang/rust/pull/63587#issuecomment-522343864>
+ url = { version = "2.1.0", features = ["serde"] }
+ quote = "1"
+-syn = { version = "1", features = ["full"] }
++syn = { version = "1", features = ["full", "visit-mut", "extra-traits", "visit"] }
+ 
+ [features]
+ deny-warnings = []
 diff --git a/src/tools/rustfmt/Cargo.toml b/src/tools/rustfmt/Cargo.toml
 index 0f5bec2dcca..c9a64f05949 100644
 --- a/src/tools/rustfmt/Cargo.toml

debian/patches/series

@@ -11,6 +11,7 @@ u-tests-ignore-arm.patch
 u-mips-fixes.diff
 u-ignore-endian-big.patch
 u-build-cargo-only-if-requested.patch
+u-fix-cross-compile-tools.patch
 #u-allow-system-compiler-rt.patch
 
 # not forwarded, or forwarded but unlikely to be merged

debian/patches/u-fix-cross-compile-tools.patch

@@ -0,0 +1,16 @@
+Forwarded: https://github.com/rust-lang/rust/pull/85326
+
+--- a/src/bootstrap/tool.rs
++++ b/src/bootstrap/tool.rs
+@@ -52,7 +52,10 @@
+         let is_optional_tool = self.is_optional_tool;
+ 
+         match self.mode {
+-            Mode::ToolRustc => builder.ensure(compile::Rustc { compiler, target }),
++            Mode::ToolRustc => {
++                builder.ensure(compile::Std { compiler, target: compiler.host });
++                builder.ensure(compile::Rustc { compiler, target });
++            }
+             Mode::ToolStd => builder.ensure(compile::Std { compiler, target }),
+             Mode::ToolBootstrap => {} // uses downloaded stage0 compiler libs
+             _ => panic!("unexpected Mode for tool build"),