Do static linking by default

[brson]

I currently believe there is little hope that Rust libraries can offer any meaningful binary forward compatibility or upgradability. Since this is one of the primary benefits of dynamic linking (the other being reduction in code size), and static linking having other advantages of convenience, perhaps we should prefer static linking by default.

cc #10208 #10188

[brson]

Nominating, though I think we can live without this for 1.0

[pnkfelix]

P-low, not necessary to do this (or decide about doing it) for 1.0.

[wycats]

As an embedded user of Rust, this would be really really nice and would make 1.0 significantly more appealing.

[liigo]

+1 for static linking by default

[alexcrichton]

I believe that as it stands today #10740 blocks this bug.

[alexcrichton]

Now that #10740 is closed, I'm still not entirely convinced that we should do this by default. This makes linking fn main() {} 4.5x slower from 20ms to 90ms, which is a pretty noticeable hit when dealing with small programs. We should investigate how to optimize compile times for small programs and then I believe that static linking would be an excellent default.

[alexcrichton]

Closing, we prefer static linking by default, and #11253 is the tracker for whether we should output an rlib or a dylib by default for libraries.