Rename OS(DARWIN) to OS(MACOSX).

Source/core/platform/LayoutUnit.h

 /*
  * Copyright (c) 2012, Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 113 matching lines @@
         REPORT_OVERFLOW(value > std::numeric_limits<int>::min() && value < std::numeric_limits<int>::max());
         m_value = static_cast<int>(value);
     }
 
     LayoutUnit abs() const
     {
         LayoutUnit returnValue;
         returnValue.setRawValue(::abs(m_value));
         return returnValue;
     }
-#if OS(DARWIN)
+#if OS(MACOSX)
     int wtf_ceil() const
 #else
     int ceil() const
 #endif
     {
         if (UNLIKELY(m_value >= INT_MAX - kFixedPointDenominator + 1))
             return intMaxForLayoutUnit;
 
         if (m_value >= 0)
             return (m_value + kFixedPointDenominator - 1) / kFixedPointDenominator;
@@ skipping 645 matching lines @@
 }
 
 inline bool isIntegerValue(const LayoutUnit value)
 {
     return value.toInt() == value;
 }
 
 } // namespace WebCore
 
 #endif // LayoutUnit_h