Use std::is_trivial instead of is_trivially_copyable.

The oldest versions of GCC we support (before 5) didn't support that
trait. is_trivial is stronger superset that clang::Token fulfills, so
just use that instead.

llvm-svn: 314391
diff --git a/clang/lib/Lex/MacroArgs.cpp b/clang/lib/Lex/MacroArgs.cpp
index b96b1a8..37a7d5c 100644
--- a/clang/lib/Lex/MacroArgs.cpp
+++ b/clang/lib/Lex/MacroArgs.cpp
@@ -62,11 +62,11 @@
 
   // Copy the actual unexpanded tokens to immediately after the result ptr.
   if (!UnexpArgTokens.empty()) {
-    static_assert(std::is_trivially_copyable<Token>::value,
+    static_assert(std::is_trivial<Token>::value,
                   "assume trivial copyability if copying into the "
                   "uninitialized array (as opposed to reusing a cached "
                   "MacroArgs)");
-    std::copy(UnexpArgTokens.begin(), UnexpArgTokens.end(), 
+    std::copy(UnexpArgTokens.begin(), UnexpArgTokens.end(),
               Result->getTrailingObjects<Token>());
   }