RFC: Junction Point/NT Symlink Support [2]

[Erich E. Hoover]

I would love any and all feedback on updated versions of my "Junction
Point" patches, which are now available in staging:
https://github.com/wine-staging/wine-staging/tree/master/patches/ntdll-Junction_Points

Major changes since the last publicly available version are:
1) Use of renameat2(..., RENAME_EXCHANGE), when possible
2) You can now tell the difference between Junction Points and NT
Symlinks (the reparse tag is stored in the Unix Symlink as a magic
string)
3) Support has been added for absolute symlinks
4) Support has been added for relative symlinks
5) Support has been added for file symlinks
6) Significantly more tests have been added and quirky delete
behaviors identified and fixed
7) CreateSymbolicLink[A|W] is now implemented with
DeviceIoControl(...,FSCTL_SET_REPARSE_POINT,...)

Thank you in advance to those who look these patches over, your
feedback is greatly appreciated.

Best,
Erich