Don't impose Werror on users of BoringSSL

Change-Id: Ibc52fbe362728134fce3c90ee47a23065a2e31b2
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/74087
Reviewed-by: Adam Langley <agl@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: Adam Langley <agl@google.com>

.bazelrc

@@ -33,6 +33,12 @@ build:linux --cxxopt=-std=c++17
 build:macos --cxxopt=-std=c++17
 build:windows --cxxopt=/std:c++17
 
+# Our own builds should strictly build without warnings, but we don't add those
+# in targets like other flags because we can't assume all users will have clean
+# builds too.
+build:linux --cxxopt=-Werror
+build:macos --cxxopt=-Werror
+
 # Without setting a minimum macOS version, std::optional does not work.
 build:macos --cxxopt=-mmacosx-version-min=10.15
 

util/util.bzl

@@ -22,7 +22,6 @@ load("@rules_cc//cc:defs.bzl", "cc_binary", "cc_library", "cc_test")
 gcc_copts = [
     # This list of warnings should match those in the top-level CMakeLists.txt.
     "-Wall",
-    "-Werror",
     "-Wformat=2",
     "-Wsign-compare",
     "-Wmissing-field-initializers",