Resource flag is larger than necessary

[nikomatsakis]

Currently resources have a flag of size "int", meaning 32 or 64 bits. This is pretty large for a 1-bit flag. Ideally, it would be a single bit and then allow the alignment code to ensure that the contents of the resource are properly aligned. After the port to x86_64 is running smoothly this would be a good thing to tackle.

[nikomatsakis]

I've gone ahead and tagged the places in the code that would need to change with "FIXME #1884"