Update memprof to C++17.

Author: levlam

memprof/memprof.cpp

@@ -291,22 +291,25 @@ void *memalign(std::size_t alignment, std::size_t size) {
 }
 }
 
-// c++14 guarantees that it is enough to override these two operators.
+// c++17 guarantees that it is enough to override these 4 operators
 void *operator new(std::size_t count) {
   return malloc_with_frame(count, get_backtrace());
 }
 void operator delete(void *ptr) noexcept(true) {
   free(ptr);
 }
+void *operator new(std::size_t count, std::align_val_t al) {
+  return memalign(static_cast<std::size_t>(al), count);
+}
+void operator delete(void *ptr, std::align_val_t al) noexcept {
+  free(ptr);
+}
+
 // because of gcc warning: the program should also define 'void operator delete(void*, std::size_t)'
 void operator delete(void *ptr, std::size_t) noexcept(true) {
   free(ptr);
 }
 
-// c++17
-// void *operator new(std::size_t count, std::align_val_t al);
-// void operator delete(void *ptr, std::align_val_t al);
-
 #else
 bool is_memprof_on() {
   return false;