feat: Implement _system_library_build_file

Before:

```console
$ bazel run //:sqlite_data_example
ERROR: /private/var/tmp/_bazel_jsimard/e01a47dc03c304f8327e2ce75a78ef77/external/rules_swift_package_manager++swift_deps+swiftpkg_grdb.swift/BUILD.bazel:46:14: in deps attribute of swift_library rule @@rules_swift_package_manager++swift_deps+swiftpkg_grdb.swift//:GRDB.rspm: target '@@rules_swift_package_manager++swift_deps+swiftpkg_grdb.swift//:GRDBSQLite.rspm' does not exist
ERROR: /private/var/tmp/_bazel_jsimard/e01a47dc03c304f8327e2ce75a78ef77/external/rules_swift_package_manager++swift_deps+swiftpkg_grdb.swift/BUILD.bazel:46:14: Analysis of target '@@rules_swift_package_manager++swift_deps+swiftpkg_grdb.swift//:GRDB.rspm' (config: 945dbe2) failed
ERROR: Analysis of target '//:sqlite_data_example' failed; build aborted: Analysis failed
INFO: Elapsed time: 15.202s, Critical Path: 0.00s
INFO: 1 process: 1 internal.
ERROR: Build did NOT complete successfully
ERROR: Build failed. Not running target
```

After:

```console
$ bazel run //:sqlite_data_example
INFO: Analyzed target //:sqlite_data_example (2 packages loaded, 108 targets configured).
INFO: Found 1 target...
Target //:sqlite_data_example up-to-date:
  bazel-bin/sqlite_data_example
INFO: Elapsed time: 0.762s, Critical Path: 0.01s
INFO: 1 process: 131 action cache hit, 1 internal.
INFO: Build completed successfully, 1 total action
INFO: Running command line: bazel-bin/sqlite_data_example
1 Frodo Baggins
3 Samwise Gamgee
```

Author: jpsim

examples/sqlite_data_example/.bazelrc

@@ -0,0 +1,8 @@
+# Import Shared settings
+import %workspace%/../../shared.bazelrc
+
+# Import CI settings.
+import %workspace%/../../ci.bazelrc
+
+# Try to import a local.rc file; typically, written by CI
+try-import %workspace%/../../local.bazelrc

examples/sqlite_data_example/BUILD.bazel

@@ -0,0 +1,11 @@
+load("@build_bazel_rules_swift//swift:swift.bzl", "swift_binary")
+
+swift_binary(
+    name = "sqlite_data_example",
+    srcs = ["example.swift"],
+    module_name = "sqlite_data_example",
+    visibility = ["//visibility:public"],
+    deps = [
+        "@swiftpkg_sqlite_data//:SQLiteData",
+    ],
+)

examples/sqlite_data_example/MODULE.bazel

@@ -0,0 +1,49 @@
+bazel_dep(
+    name = "rules_swift_package_manager",
+    version = "0.0.0",
+)
+local_path_override(
+    module_name = "rules_swift_package_manager",
+    path = "../..",
+)
+
+bazel_dep(name = "cgrindel_bazel_starlib", version = "0.27.0")
+bazel_dep(name = "bazel_skylib", version = "1.8.1")
+bazel_dep(name = "apple_support", version = "1.23.1")
+bazel_dep(
+    name = "rules_swift",
+    version = "3.1.2",
+    repo_name = "build_bazel_rules_swift",
+)
+bazel_dep(
+    name = "rules_apple",
+    version = "4.2.0",
+    repo_name = "build_bazel_rules_apple",
+)
+
+bazel_dep(
+    name = "bazel_skylib_gazelle_plugin",
+    version = "1.8.1",
+    dev_dependency = True,
+)
+bazel_dep(
+    name = "gazelle",
+    version = "0.45.0",
+    dev_dependency = True,
+    repo_name = "bazel_gazelle",
+)
+
+swift_deps = use_extension(
+    "@rules_swift_package_manager//:extensions.bzl",
+    "swift_deps",
+)
+swift_deps.from_package(
+    resolved = "//:Package.resolved",
+    swift = "//:Package.swift",
+)
+use_repo(
+    swift_deps,
+    "swift_package",
+    "swiftpkg_sqlite_data",
+    "swiftpkg_swift_tagged",
+)

examples/sqlite_data_example/Package.resolved

@@ -0,0 +1,11 @@
+// swift-tools-version: 6.0
+
+import PackageDescription
+
+let package = Package(
+    name: "sqlite_data_example",
+    dependencies: [
+        .package(url: "https://github.com/pointfreeco/sqlite-data", exact: "1.0.0"),
+        .package(url: "https://github.com/pointfreeco/swift-tagged", from: "0.10.0"),
+    ]
+)

examples/sqlite_data_example/Package.swift

@@ -0,0 +1 @@
+# Intentionally blank: Using bzlmod

examples/sqlite_data_example/WORKSPACE

@@ -0,0 +1 @@
+# Intentionally blank: Force bzlmod to strict mode

examples/sqlite_data_example/WORKSPACE.bzlmod

@@ -0,0 +1,13 @@
+#!/usr/bin/env bash
+
+set -eou pipefail
+
+# Use the Bazel binary specified by the integration test. Otherise, fall back
+# to bazel.
+bazel="${BIT_BAZEL_BINARY:-bazel}"
+
+# Test resolving the package via the `swift_package` repo.
+"${bazel}" run @swift_package//:resolve
+
+# Ensure that it builds.
+"${bazel}" build //...

examples/sqlite_data_example/do_test

@@ -0,0 +1,40 @@
+import SQLiteData
+
+@Table
+private struct Hobbit: Equatable {
+  let id: Int
+  var firstName: String
+  var lastName: String
+}
+
+@main
+struct Main {
+  static func main() async throws {
+    let database = try DatabaseQueue()
+    try await withDependencies {
+      $0.defaultDatabase = database
+    } operation: {
+      try await database.write { db in
+        try #sql(
+          """
+          CREATE TABLE "hobbits" (
+          "id" INTEGER PRIMARY KEY AUTOINCREMENT,
+          "firstName" TEXT NOT NULL,
+          "lastName" TEXT NOT NULL
+          )
+          """
+        )
+        .execute(db)
+        _ = try Hobbit.insert { Hobbit(id: 1, firstName: "Frodo", lastName: "Baggins") }.execute(db)
+        _ = try Hobbit.insert { Hobbit(id: 3, firstName: "Samwise", lastName: "Gamgee") }.execute(db)
+      }
+
+      @FetchAll var hobbits: [Hobbit]
+
+      try await $hobbits.load()
+      for hobbit in hobbits {
+        print(hobbit.id, hobbit.firstName, hobbit.lastName)
+      }
+    }
+  }
+}

examples/sqlite_data_example/example.swift

@@ -709,12 +709,60 @@ def _starlarkify_clang_attrs(repository_ctx, attrs):
 
 # MARK: - System Library Targets
 
-# GH009(chuck): Remove unused-variable directives
-
-# buildifier: disable=unused-variable
 def _system_library_build_file(target):
-    # GH009(chuck): Implement _system_library_build_file
-    return None
+    # System libraries are typically C/Objc libraries that need to be exposed to Swift.
+    # We generate a cc_library with a swift_interop_hint for proper Swift interop.
+
+    bzl_target_name = target.label.name
+
+    # Build the cc_library attributes
+    attrs = {}
+
+    # For system libraries, sources is always empty. We need to use glob to find files.
+    # Look for all .h files in the target path
+    hdrs_glob = paths.join(target.path, "**/*.h")
+
+    # System libraries typically have headers and a module.modulemap
+    # We'll use glob patterns to find them
+    attrs["hdrs"] = scg.new_fn_call("glob", [hdrs_glob])
+
+    # Create swift_interop_hint for C/Swift interop
+    aspect_hint_target_name = pkginfo_targets.swift_hint_label_name(bzl_target_name)
+
+    load_stmts = [swift_interop_hint_load_stmt]
+    decls = []
+
+    # Create the swift_interop_hint
+    decls.append(
+        build_decls.new(
+            kind = swift_kinds.interop_hint,
+            name = aspect_hint_target_name,
+            attrs = {
+                # For system libraries, we often don't have a module map file
+                # Set to None and let rules_swift generate one if needed
+                "module_map": None,
+                "module_name": target.c99name,
+            },
+        ),
+    )
+
+    # Add aspect_hints to cc_library
+    attrs["aspect_hints"] = [":{}".format(aspect_hint_target_name)]
+    attrs["visibility"] = ["//visibility:public"]
+
+    # Create the cc_library
+    decls.append(
+        build_decls.new(
+            kind = clang_kinds.library,
+            name = bzl_target_name,
+            attrs = attrs,
+        ),
+    )
+
+    return build_files.new(
+        load_stmts = load_stmts,
+        decls = decls,
+    )
 
 # MARK: - Apple xcframework Targets