Fuchsia: Memory reservation and partial unmapping

runtime/vm/virtual_memory_macos.cc

Index: runtime/vm/virtual_memory_macos.cc
diff --git a/runtime/vm/virtual_memory_macos.cc b/runtime/vm/virtual_memory_macos.cc
index 6f42b558e9a42c5bf3e2629b76ff80e215c42583..c3b004d808693a7bc83445138c90e5a3dc4ce830 100644
--- a/runtime/vm/virtual_memory_macos.cc
+++ b/runtime/vm/virtual_memory_macos.cc
@@ -60,7 +60,9 @@ VirtualMemory::~VirtualMemory() {
 }
 
 
-bool VirtualMemory::FreeSubSegment(void* address, intptr_t size) {
+bool VirtualMemory::FreeSubSegment(int32_t handle,
+                                   void* address,
+                                   intptr_t size) {
   unmap(address, size);
   return true;
 }