Fix build on GCC 4.7.

c++/src/capnp/compiler/node-translator.c++

@@ -1146,6 +1146,8 @@ NodeTranslator::BrandedDecl NodeTranslator::BrandScope::decompileType(
       KJ_UNREACHABLE;
     }
   }
+
+  KJ_UNREACHABLE;
 }
 
 kj::Maybe<NodeTranslator::BrandedDecl> NodeTranslator::BrandScope::compileDeclExpression(
@@ -1252,6 +1254,8 @@ kj::Maybe<NodeTranslator::BrandedDecl> NodeTranslator::BrandScope::compileDeclEx
       }
     }
   }
+
+  KJ_UNREACHABLE;
 }
 
 // =======================================================================================
@@ -1270,7 +1274,7 @@ NodeTranslator::NodeTranslator(
   compileNode(decl, wipNode.get());
 }
 
-NodeTranslator::~NodeTranslator() {}
+NodeTranslator::~NodeTranslator() noexcept(false) {}
 
 NodeTranslator::NodeSet NodeTranslator::getBootstrapNode() {
   auto nodeReader = wipNode.getReader();

c++/src/capnp/compiler/node-translator.h

@@ -121,7 +121,7 @@ public:
   // `displayName`, `id`, `scopeId`, and `nestedNodes` already initialized.  The `NodeTranslator`
   // fills in the rest.
 
-  ~NodeTranslator();
+  ~NodeTranslator() noexcept(false);
 
   struct NodeSet {
     schema::Node::Reader node;

c++/src/capnp/schema.c++

@@ -692,6 +692,11 @@ ListSchema ListSchema::of(schema::Type::Which primitiveType) {
 }
 
 ListSchema ListSchema::of(schema::Type::Reader elementType, Schema context) {
+  // This method is deprecated because it can only be implemented in terms of other deprecated
+  // methods. Temporarily disable warnings for those other deprecated methods.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
   switch (elementType.which()) {
     case schema::Type::VOID:
     case schema::Type::BOOL:
@@ -728,6 +733,7 @@ ListSchema ListSchema::of(schema::Type::Reader elementType, Schema context) {
 
   // Unknown type is acceptable.
   return ListSchema(elementType.which());
+#pragma GCC diagnostic pop
 }
 
 StructSchema ListSchema::getStructElementType() const {