Issue 8370 - Fix deprecated message during Linux Phobos build.

This change fixes Linux builds only. Other Posix based OS's will still use the deprecated alias from the Posix module. (This is the same behavior as the garbage collector module.)
fix Issue 13056 - [2.066.0-b1] Regression: Error: template std.path.baseName cannot deduce function from argument types !()(DirEntry)
Changed tabs to spaces
Merge pull request #2295 from adamsaka/issue_8370

Issue 8370 - Fix deprecated message during Linux Phobos build.
Merge pull request #2306 from WalterBright/fix13056

fix Issue 13056 - [2.066.0-b1] Regression: Error: template std.path.base...