Fix some MSVC problems.

c++/src/kj/function.h

@@ -223,7 +223,6 @@ public:
   }
 
   FunctionParam(const FunctionParam& other) = default;
-  FunctionParam(FunctionParam& other) = default;
   FunctionParam(FunctionParam&& other) = default;
   // Magically, a plain copy works.
 

c++/src/kj/table.c++

@@ -26,7 +26,7 @@
 namespace kj {
 namespace _ {
 
-static constexpr uint lg(uint value) {
+static inline uint lg(uint value) {
   // Compute floor(log2(value)).
   return sizeof(uint) * 8 - 1 - __builtin_clz(value);
 }

c++/src/kj/table.h

@@ -887,7 +887,7 @@ KJ_ALWAYS_INLINE(void compilerBarrier()) {
   // writes that occur after this call. We need this in a couple places below to prevent C++
   // strict aliasing rules from breaking things.
 #if _MSC_VER
-  _ReadWriteBarrier()
+  _ReadWriteBarrier();
 #else
   __asm__ __volatile__("": : :"memory");
 #endif