Some large file support enhancements

The normal functions should be aliases to the *64 functions,
even if _LARGEFILE64_SOURCE is false. _LARGEFILE64_SOURCE is
more or less deprecated.
adjust system internal structures like _SYSTEM_PROCESS_INFORMATION to Win64
code styling and comments
fill system structs with more field info
remove space
Merge pull request #381 from rainers/win64_dll_init

Win64: fix DLL loading for multi threaded applications
Merge pull request #310 from jpf91/lfs

Some large file support enhancements