std: add a Clone impl for HashSet.
Fixed #8451 - extra::stats::write_boxplot() applied to negative or zero sample values
Fixed option_env! type

The type of the result of option_env! was not fully specified in the
None case, leading to type check failures in the case where the variable
was not defined (e.g. option_env!("FOO").is_none()).
remove more dead code from the old `for`
doc: Add -M and -L option to po4a
doc: Update .pot files
doc: Generate .po files for Japanse translations
tutorial: Add Japanese translation
rustc: Give a hint when a static method call has fewer than expected type parameters

In this case, it's likely to be that the user forgot the `self` type, so
say so.

Closes #4096
Remove unnecessary return
std::at_vec: add benchmarks
librustc: Allow vector repeat exprs in statics.
Add RngUtils::sample() method for reservoir sampling from iterators
Remove unused automatic cfg bindings Fixes #7169
Add test for repeat expr in statics.
Add a bunch of tests for closed issues

Closes #3907
Closes #5493
Closes #4464
Closes #4759
Closes #5666
Closes #5884
Closes #5926
Closes #6318
Closes #6557
Closes #6898
Closes #6919
Closes #7222
auto merge of #8477 : catamorphism/rust/issue-4096, r=msullivan

r? @msullivan ...e parameters

In this case, it's likely to be that the user forgot the `self` type, so
say so.

Closes #4096
auto merge of #8439 : huonw/rust/hashset-clone, r=cmr

Closes #5581.
auto merge of #8440 : sfackler/rust/env-fix, r=pcwalton

The type of the result of option_env! was not fully specified in the
None case, leading to type check failures in the case where the variable
was not defined (e.g. option_env!("FOO").is_none()).

Also cleaned up some compilation warnings.
Methodyfied the string ascii extionsion functions
Added into_owned() method for vectors
Added DoubleEnded Iterator impl to Option
Renamed nil.rs to unit.rs