Enable warnings as errors during tests (#10482)
* Enable warnings as errors by default for test builds
* Fixing C++ warnings
* Adding host flags, and enabling warnings as error for non-C++ too
* Switch to BUILD copts instead of bazelrc to treat Windows as a snowflake
* Disable warnings as errors on Windows, since it doesn't like the c++14 flag
diff --git a/.bazelrc b/.bazelrc
index 732859d..554440c 100644
--- a/.bazelrc
+++ b/.bazelrc
@@ -1 +1 @@
-build --cxxopt=-std=c++14
\ No newline at end of file
+build --cxxopt=-std=c++14 --host_cxxopt=-std=c++14
