Fixes an issue related to a wrong variable type (#182)

[lpinca]

The issue was generated by passing the negative value of an unsigned variable as parameter of the function AdjustAmountOfExternalAllocatedMemory.

The version of V8 included in node v0.8.x changed the param type of the function AdjustAmountOfExternalAllocatedMemory from int to intptr_t.

The result of this change is that if foo is an unsigned variable, passing -foo to AdjustAmountOfExternalAllocatedMemory is the same of passing the value (UINT_MAX - foo + 1) and not the expected - foo.

Changing the type of the passed variable to int16_t fixed the issue.

[tj]

I suppose we could just cast no?

[lpinca]

Ok, but it doesn't have much sense to declare a variable unsigned when you plan on getting its negative value.
Why don't just declare it intptr_t at this point?

[tj]

well it doesn't really make sense to give the length of something a signed value either, but keep in mind we have a range of 4294967296 with the unsigned int so we should be safe :p node does this all over too with size_t

[Dman9296]

Nothing but the best