Add a few more anonymous namespaces around struts

Later we'll probably want to square our preferred styles against this
stricter requirement. (Maybe we should just prefer to put everything
file-local in anonymous namespaces rather than mark things static? Not
sure. I don't like that it's hard to see whether something is static,
but if we have to use this for types anyway...)

Bug: 384186552
Change-Id: Ie86a56b1c7358a32262f0b9c4edb3e503aa3d08a
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/74547
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
Auto-Submit: David Benjamin <davidben@google.com>
Commit-Queue: Adam Langley <agl@google.com>

crypto/hrss/hrss.cc

@@ -1835,6 +1835,8 @@ static void poly_lift(struct poly *out, const struct poly *a) {
   poly_normalize(out);
 }
 
+namespace {
+
 struct public_key {
   struct poly ph;
 };
@@ -1845,6 +1847,8 @@ struct private_key {
   uint8_t hmac_key[32];
 };
 
+}  // namespace
+
 // public_key_from_external converts an external public key pointer into an
 // internal one. Externally the alignment is only specified to be eight bytes
 // but we need 16-byte alignment. We could annotate the external struct with

crypto/kyber/kyber.cc

@@ -575,6 +575,8 @@ static void vector_decompress(vector *a, int bits) {
   }
 }
 
+namespace {
+
 struct public_key {
   vector t;
   uint8_t rho[32];
@@ -607,6 +609,8 @@ static struct private_key *private_key_from_external(
   return (struct private_key *)external;
 }
 
+}  // namespace
+
 // Calls |KYBER_generate_key_external_entropy| with random bytes from
 // |RAND_bytes|.
 void KYBER_generate_key(uint8_t out_encoded_public_key[KYBER_PUBLIC_KEY_BYTES],