AddressSanitizer: get rid of stdlib.h and add (smaller) stddef.h instead

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@151162 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/asan/asan_win.cc b/lib/asan/asan_win.cc
index 86bcc2c..2692b0d 100644
--- a/lib/asan/asan_win.cc
+++ b/lib/asan/asan_win.cc
@@ -16,6 +16,7 @@
 
 #include <dbghelp.h>
 #include <stdio.h>  // FIXME: get rid of this.
+#include <stdlib.h>
 
 #include <new>  // FIXME: temporarily needed for placement new in AsanLock.
 
@@ -262,6 +263,10 @@
   _exit(exitcode);
 }
 
+int Atexit(void (*function)(void)) {
+  return atexit(function);
+}
+
 }  // namespace __asan
 
 #endif  // _WIN32