Update toolchain paths for clang-20. (#7071)

Re-landing #7028 now that clang-20 has landed again.

(cherry picked from commit c86fb92)

Author: rvandermeulen

taskcluster/scripts/toolchain/cross-compile-setup.sh

@@ -6,12 +6,12 @@ export PATH=$PATH:/builds/worker/clang/bin
 export ORG_GRADLE_PROJECT_RUST_ANDROID_GRADLE_TARGET_X86_64_APPLE_DARWIN_NSS_STATIC=1
 export ORG_GRADLE_PROJECT_RUST_ANDROID_GRADLE_TARGET_X86_64_APPLE_DARWIN_NSS_DIR=/builds/worker/checkouts/vcs/libs/desktop/darwin/nss
 # x86_64 Darwin
-export ORG_GRADLE_PROJECT_RUST_ANDROID_GRADLE_TARGET_X86_64_APPLE_DARWIN_CC=/builds/worker/clang/bin/clang-19
+export ORG_GRADLE_PROJECT_RUST_ANDROID_GRADLE_TARGET_X86_64_APPLE_DARWIN_CC=/builds/worker/clang/bin/clang-20
 export ORG_GRADLE_PROJECT_RUST_ANDROID_GRADLE_TARGET_X86_64_APPLE_DARWIN_TOOLCHAIN_PREFIX=/builds/worker/cctools/bin
 export ORG_GRADLE_PROJECT_RUST_ANDROID_GRADLE_TARGET_X86_64_APPLE_DARWIN_AR=/builds/worker/cctools/bin/x86_64-apple-darwin-ar
 export ORG_GRADLE_PROJECT_RUST_ANDROID_GRADLE_TARGET_X86_64_APPLE_DARWIN_RANLIB=/builds/worker/cctools/bin/x86_64-apple-darwin-ranlib
 export ORG_GRADLE_PROJECT_RUST_ANDROID_GRADLE_TARGET_X86_64_APPLE_DARWIN_LD_LIBRARY_PATH=/builds/worker/clang/lib
-export ORG_GRADLE_PROJECT_RUST_ANDROID_GRADLE_TARGET_X86_64_APPLE_DARWIN_RUSTFLAGS="-C linker=/builds/worker/clang/bin/clang-19 -C link-arg=-fuse-ld=/builds/worker/cctools/bin/x86_64-apple-darwin-ld -C link-arg=-B -C link-arg=/builds/worker/cctools/bin -C link-arg=-target -C link-arg=x86_64-apple-darwin -C link-arg=-isysroot -C link-arg=/tmp/MacOSX11.0.sdk -C link-arg=-Wl,-syslibroot,/tmp/MacOSX11.0.sdk -C link-arg=-Wl,-dead_strip"
+export ORG_GRADLE_PROJECT_RUST_ANDROID_GRADLE_TARGET_X86_64_APPLE_DARWIN_RUSTFLAGS="-C linker=/builds/worker/clang/bin/clang-20 -C link-arg=-fuse-ld=/builds/worker/cctools/bin/x86_64-apple-darwin-ld -C link-arg=-B -C link-arg=/builds/worker/cctools/bin -C link-arg=-target -C link-arg=x86_64-apple-darwin -C link-arg=-isysroot -C link-arg=/tmp/MacOSX11.0.sdk -C link-arg=-Wl,-syslibroot,/tmp/MacOSX11.0.sdk -C link-arg=-Wl,-dead_strip"
 # For ring's use of `cc`.
 export ORG_GRADLE_PROJECT_RUST_ANDROID_GRADLE_TARGET_X86_64_APPLE_DARWIN_CFLAGS_x86_64_apple_darwin="-B /builds/worker/cctools/bin -target x86_64-apple-darwin -isysroot /tmp/MacOSX11.0.sdk -Wl,-syslibroot,/tmp/MacOSX11.0.sdk -Wl,-dead_strip"
 
@@ -39,10 +39,6 @@ tar -xf clang-dist-toolchain.tar.xz
 mv builds/worker/toolchains/clang clang
 rm clang-dist-toolchain.tar.xz
 
-# The `clang-19` symlink is an absolute path, but our build script puts the `clang` binary in a
-# slightly different place.  Overwrite the symlink to fix this.
-ln -sf /builds/worker/clang/bin/clang-19 /builds/worker/clang/bin/clang
-
 popd
 
 pushd /tmp || exit