Better document supports_dynamic_linker

.github/workflows/release_notes_template.txt

@@ -60,7 +60,12 @@ And add the following section to your .bazelrc file:
 # Not needed after https://github.com/bazelbuild/bazel/issues/7260 is closed
 build --incompatible_enable_cc_toolchain_resolution
 
-# Tell Bazel to pass the right flags for llvm-ar, not libtool. Only needed if you are building on darwin.
-# See https://github.com/bazelbuild/bazel/blob/5c75d0acec21459bbb13520817e3806e1507e907/tools/cpp/unix_cc_toolchain_config.bzl#L1000-L1024
+# For macOS only:
+
+# Needed for Bazel versions before 7.
+# Without this, one can use `--linkopt='-undefined dynamic_lookup'`.
+# This feature is intentionally not supported on macOS.
+build --features=-supports_dynamic_linker
+# Not needed after https://github.com/grailbio/bazel-toolchain/pull/229.
 build --features=-libtool
 ```

tests/.bazelrc

@@ -1,2 +1 @@
 build --incompatible_enable_cc_toolchain_resolution
-build --features=-libtool

tests/scripts/bazel.sh

@@ -50,10 +50,15 @@ common_test_args=(
   "--test_output=errors"
 )
 
-# TODO: Remove this once we no longer support bazel 6.x.
-# This feature isn't intentionally supported on macOS.
 if [[ ${short_uname} == 'Darwin' ]]; then
-  common_test_args+=(--features=-supports_dynamic_linker)
+  common_test_args+=(
+    # Needed for Bazel versions before 7.
+    # Without this, one can use `--linkopt='-undefined dynamic_lookup'`.
+    # This feature is intentionally not supported on macOS.
+    --features=-supports_dynamic_linker
+    # Not needed after https://github.com/grailbio/bazel-toolchain/pull/229.
+    --features=-libtool
+  )
 fi
 
 # Do not run autoconf to configure local CC toolchains.