Fix more warnings.

c++/src/kj/array.h

@@ -129,8 +129,8 @@ class Array {
   // single objects.
 
 public:
-  inline Array(): ptr(nullptr), size_(0) {}
-  inline Array(decltype(nullptr)): ptr(nullptr), size_(0) {}
+  inline Array(): ptr(nullptr), size_(0), disposer(nullptr) {}
+  inline Array(decltype(nullptr)): ptr(nullptr), size_(0), disposer(nullptr) {}
   inline Array(Array&& other) noexcept
       : ptr(other.ptr), size_(other.size_), disposer(other.disposer) {
     other.ptr = nullptr;

c++/src/kj/debug-test.c++

@@ -53,7 +53,7 @@ public:
     // the child to die.
 
     int pipeFds[2];
-    pipe(pipeFds);
+    KJ_SYSCALL(pipe(pipeFds));
     pid_t child = fork();
     if (child == 0) {
       // This is the child!