Add -g in `per_object_debug_info` for Clang 12 and GCC 11
diff --git a/cc/private/toolchain/unix_cc_toolchain_config.bzl b/cc/private/toolchain/unix_cc_toolchain_config.bzl
index c3cf3ba..fa15f22 100644
--- a/cc/private/toolchain/unix_cc_toolchain_config.bzl
+++ b/cc/private/toolchain/unix_cc_toolchain_config.bzl
@@ -313,7 +313,7 @@
                 ],
                 flag_groups = [
                     flag_group(
-                        flags = ["-gsplit-dwarf"],
+                        flags = ["-gsplit-dwarf", "-g"],
                         expand_if_available = "per_object_debug_info_file",
                     ),
                 ],