diff --git a/toolchain/cc_toolchain_config.bzl b/toolchain/cc_toolchain_config.bzl
index 013a59d1..6349a979 100644
--- a/toolchain/cc_toolchain_config.bzl
+++ b/toolchain/cc_toolchain_config.bzl
@@ -208,6 +208,7 @@ def cc_toolchain_config(
     # The linker has no way of knowing if there are C++ objects; so we
     # always link C++ libraries.
     cxx_standard = compiler_configuration["cxx_standard"]
+    conly_flags = compiler_configuration["conly_flags"]
     sysroot_path = compiler_configuration["sysroot_path"]
     if stdlib == "builtin-libc++" and is_xcompile:
         stdlib = "stdc++"
@@ -380,6 +381,7 @@ def cc_toolchain_config(
         compile_flags = compile_flags,
         dbg_compile_flags = dbg_compile_flags,
         opt_compile_flags = opt_compile_flags,
+        conly_flags = conly_flags,
         cxx_flags = cxx_flags,
         link_flags = link_flags + select({str(Label("@toolchains_llvm//toolchain/config:use_libunwind")): libunwind_link_flags, "//conditions:default": []}) +
                      select({str(Label("@toolchains_llvm//toolchain/config:use_compiler_rt")): compiler_rt_link_flags, "//conditions:default": []}),
diff --git a/toolchain/internal/configure.bzl b/toolchain/internal/configure.bzl
index 37756dd9..16afd5f8 100644
--- a/toolchain/internal/configure.bzl
+++ b/toolchain/internal/configure.bzl
@@ -159,6 +159,7 @@ def llvm_config_impl(rctx):
         stdlib_dict = rctx.attr.stdlib,
         cxx_standard_dict = rctx.attr.cxx_standard,
         compile_flags_dict = rctx.attr.compile_flags,
+        conly_flags_dict = rctx.attr.conly_flags,
         cxx_flags_dict = rctx.attr.cxx_flags,
         link_flags_dict = rctx.attr.link_flags,
         archive_flags_dict = rctx.attr.archive_flags,
@@ -377,6 +378,7 @@ cc_toolchain_config(
       "stdlib": "{stdlib}",
       "cxx_standard": "{cxx_standard}",
       "compile_flags": {compile_flags},
+      "conly_flags": {conly_flags},
       "cxx_flags": {cxx_flags},
       "link_flags": {link_flags},
       "archive_flags": {archive_flags},
@@ -549,6 +551,7 @@ cc_toolchain(
         stdlib = _dict_value(toolchain_info.stdlib_dict, target_pair, "builtin-libc++"),
         cxx_standard = _dict_value(toolchain_info.cxx_standard_dict, target_pair, "c++17"),
         compile_flags = _list_to_string(_dict_value(toolchain_info.compile_flags_dict, target_pair)),
+        conly_flags = _list_to_string(toolchain_info.conly_flags_dict.get(target_pair, [])),
         cxx_flags = _list_to_string(_dict_value(toolchain_info.cxx_flags_dict, target_pair)),
         link_flags = _list_to_string(_dict_value(toolchain_info.link_flags_dict, target_pair)),
         archive_flags = _list_to_string(_dict_value(toolchain_info.archive_flags_dict, target_pair)),
diff --git a/toolchain/internal/repo.bzl b/toolchain/internal/repo.bzl
index 3bd95a93..0f17cb56 100644
--- a/toolchain/internal/repo.bzl
+++ b/toolchain/internal/repo.bzl
@@ -163,6 +163,12 @@ _compiler_configuration_attrs = {
                "target OS and arch pair you want to override " +
                "({}); empty key overrides all.".format(_target_pairs)),
     ),
+    "conly_flags": attr.string_list_dict(
+        mandatory = False,
+        doc = ("Extra flags for compiling C (not C++) files, " +
+               "for each target OS and arch pair you want to support " +
+               "({}), ".format(", ".join(_supported_os_arch_keys())) + "."),
+    ),
     "cxx_flags": attr.string_list_dict(
         mandatory = False,
         doc = ("Override for cxx_flags, replacing the default values. " +