Create a os shim for one-time initialization
Add size specific atomics for 1, 4 & 8 byte atomic operations
Merge pull request #1255 from markbenvenuto/once

Create a os shim for one-time initialization
Minor stylistic and comment cleanups, move little-endian test into the
"once" function, instead of doing work in two places, both the upper
"call once" function and the worker function.
Merge pull request #1256 from markbenvenuto/atomics_specific

Add size specific atomics for 1, 4 & 8 byte atomic operations
KNF
STATIC_ASSERT is outside of the claimed WiredTiger name space (and
far too likely to be seen in the field), prefix it with WT
SIZE_CHECK is local to include/verify_build.h, make sure it stays
there.
Simplify gcc.h, don't repeat the GCC atomic builtins, just use one version.
Break hardware.h up into gcc.h and lint.h (hardware.h is still there,
but it's mostly empty).
Remove need for gcc.h from various benchmarking/test programs.