[fuzz] Replace is_pod

With is_standard_layout and is_trivially_copyable. is_pod is deprecated
in C++20 so we should change uses of it with appropriate checks.

Bug: 402877140
Change-Id: Ie1997fcac0b05a4bdfbb67c15b1d76bfa4e3a1bc
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/77527
Reviewed-by: Adam Langley <agl@google.com>
Commit-Queue: Adam Langley <agl@google.com>

fuzz/ssl_ctx_api.cc

diff --git a/fuzz/ssl_ctx_api.cc b/fuzz/ssl_ctx_api.cc
index 24f4e9f..ca74b05 100644
--- a/fuzz/ssl_ctx_api.cc
+++ b/fuzz/ssl_ctx_api.cc
@@ -237,8 +237,10 @@
 
 template <typename T>
 static bool GetVector(std::vector<T> *out, CBS *cbs) {
-  static_assert(std::is_pod<T>::value,
-                "GetVector may only be called on POD types");
+  static_assert(
+      std::is_standard_layout<T>::value && std::is_trivially_copyable<T>::value,
+      "GetVector may only be called on standard layout, trivially copyable "
+      "types");
 
   CBS child;
   if (!CBS_get_u8_length_prefixed(cbs, &child)) {