Fix leakage of virtual address space on Linux platform.

src/platform-openbsd.cc

Index: src/platform-openbsd.cc
diff --git a/src/platform-openbsd.cc b/src/platform-openbsd.cc
index 973329b9b109b3b145444e6a3a9dc650ba659d1b..3151d18053c0cb6b3442d72aeccde5f41e7ea227 100644
--- a/src/platform-openbsd.cc
+++ b/src/platform-openbsd.cc
@@ -245,7 +245,7 @@ OS::MemoryMappedFile* OS::MemoryMappedFile::create(const char* name, int size,
 
 
 PosixMemoryMappedFile::~PosixMemoryMappedFile() {
-  if (memory_) munmap(memory_, size_);
+  if (memory_) OS::Free(memory_, size_);
   fclose(file_);
 }
 
@@ -342,7 +342,8 @@ VirtualMemory::VirtualMemory(size_t size) {
 
 VirtualMemory::~VirtualMemory() {
   if (IsReserved()) {
-    if (0 == munmap(address(), size())) address_ = MAP_FAILED;
+    OS::Free(address(), size());
+    address_ = MAP_FAILED
   }
 }