Can size_t be 64 bits?

[dimitri-xyz]

I believe this will fail if size_t is 64 bits or more and the value is requested is also more than 2^32.

libff/libff/common/utils.cpp

Lines 19 to 30 in c927821

	size_t get_power_of_two(size_t n)
	{
	n--;
	n |= n >> 1;
	n |= n >> 2;
	n |= n >> 4;
	n |= n >> 8;
	n |= n >> 16;
	n++;
	return n;
	}

Adding a similar right shift of 32 bits would solve the problem for situations when size_t has 64 bits.

[ValarDragon]

Thanks for pointing this out, will fix