Add missing sys/mman.h include on Mac
https://bugs.webkit.org/show_bug.cgi?id=98089

Patch by Jonathan Liu <net147@gmail.com> on 2013-01-16
Reviewed by Darin Adler.

The madvise function and MADV_FREE constant require sys/mman.h.

* jit/ExecutableAllocatorFixedVMPool.cpp:

git-svn-id: svn://svn.chromium.org/blink/trunk@139926 bbb929c8-8fbe-4397-9dbb-9b2b20218538
double ExecutableAllocator::memoryPressureMultiplier(size_t addedMemoryUsage)
{
    MetaAllocator::Statistics statistics = allocator->currentStatistics();
    ASSERT(statistics.bytesAllocated <= statistics.bytesReserved);
    size_t bytesAllocated = statistics.bytesAllocated + addedMemoryUsage;
    if (bytesAllocated >= statistics.bytesReserved)
        bytesAllocated = statistics.bytesReserved;
    double result = 1.0;
    size_t divisor = statistics.bytesReserved - bytesAllocated;
    if (divisor)
        result = static_cast<double>(statistics.bytesReserved) / divisor;
    if (result < 1.0)
        result = 1.0;
    return result;
}

double ExecutableAllocator::memoryPressureMultiplier(size_t addedMemoryUsage)
{
    MetaAllocator::Statistics statistics = allocator->currentStatistics();
    ASSERT(statistics.bytesAllocated <= statistics.bytesReserved);
    size_t bytesAllocated = statistics.bytesAllocated + addedMemoryUsage;
    if (bytesAllocated >= statistics.bytesReserved)
        bytesAllocated = statistics.bytesReserved;
    double result = 1.0;
    size_t divisor = statistics.bytesReserved - bytesAllocated;
    if (divisor)
        result = static_cast<double>(statistics.bytesReserved) / divisor;
    if (result < 1.0)
        result = 1.0;
    return result;
}
