build-bazel-package: add dontAddBazelOpts arg
build-bazel-package: add dontAddBazelOpts arg

This adds an option to skip adding --copt and --linkopt to Bazel
flags. In some cases, Bazel doesn’t like these flags, like when a
custom toolchain is being used (as opposed to the builtin one. The
compiler can still get the dependencies since it is invoked through
gcc wrapper and picks up the NIX_CFLAGS_COMPILE / NIX_LDFLAGS.

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