Remove include of stdlib.h from SkTypes.h.

tests/RTConfRegistryTest.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkRTConf.h"
 #include "Test.h"
 
+#include <stdlib.h>
+
 // Friended proxy for SkRTConfRegistry::parse()
 template <typename T>
 bool test_rt_conf_parse(SkRTConfRegistry* reg, const char* key, T* value) {
     return reg->parse(key, value);
 }
 
 static void portable_setenv(const char* key, const char* value) {
 #ifdef SK_BUILD_FOR_WIN32
     _putenv_s(key, value);
 #else
     setenv(key, value, 1);
 #endif
 }
 
 DEF_TEST(SkRTConfRegistry, reporter) {
     SkRTConfRegistry reg;
 
     portable_setenv("skia_nonexistent_item", "132");
     int result = 0;
     test_rt_conf_parse(&reg, "nonexistent.item", &result);
     REPORTER_ASSERT(reporter, result == 132);
 }