It's better to avoid references to this global variable, but, in the
cases where it's needed, such as in std.debug.print and collecting stack
traces, better to share the same instance.
Acts as a replacement for `addSharedLibrary` and `addStaticLibrary`, but
linking mode can be changed more easily in build.zig, for example:
In library:
```zig
const linkage = b.option(std.builtin.LinkMode, "linkage", "Link mode for a foo_bar library") orelse .static; // or other default
const lib = b.addLibrary(.{
.linkage = linkage,
.name = "foo_bar",
.root_module = mod,
});
```
In consumer:
```zig
const dep_foo_bar = b.dependency("foo_bar", .{
.target = target,
.optimize = optimize,
.linkage = .static // or dynamic
});
mod.linkLibrary(dep_foor_bar.artifact("foo_bar"));
```
It also matches nicely with `linkLibrary` name.
Signed-off-by: Eric Joldasov <bratishkaerik@landless-city.net>
Andrew Kelley