Bazel: Add Abseil C++ dependency.

Author: sashabu

misc/bazel/workspace.bzl

@@ -43,3 +43,13 @@ def codeql_workspace(repository_name = "codeql"):
             "https://github.com/bazelbuild/bazel-skylib/releases/download/1.4.1/bazel-skylib-1.4.1.tar.gz",
         ],
     )
+
+    maybe(
+        repo_rule = http_archive,
+        name = "absl",
+        sha256 = "cec2e5bf780532bd0ac672eb8d43c0f8bbe84ca5df8718320184034b7f59a398",
+        urls = [
+            "https://github.com/abseil/abseil-cpp/archive/d2c5297a3c3948de765100cb7e5cccca1210d23c.tar.gz",
+        ],
+        strip_prefix = "abseil-cpp-d2c5297a3c3948de765100cb7e5cccca1210d23c",
+    )