Fixes Issue 9339 - Uniform for enums.
Fixes Issue 9444 - Exception must be thrown on Posix when shell() call fails.
Merge pull request #1086 from AndrejMitrovic/Fix9339

Issue 9339 - std.random.uniform for enums
Merge pull request #1135 from AndrejMitrovic/Fix9444

Issue 9444 - Exception must be thrown on Posix when shell() call fails