This change is seemingly insignificant but I actually agonized over this
for three days. Some other things I considered:
* (status quo in master branch) make Compile step creation functions
accept a Target.Query and delete the ResolvedTarget struct.
- downside: redundantly resolve target queries many times
* same as before but additionally add a hash map to cache target query
resolutions.
- downside: now there is a hash map that doesn't actually need to
exist, just to make the API more ergonomic.
* add is_native_os and is_native_abi fields to std.Target and use it
directly as the result of resolving a target query.
- downside: they really don't belong there. They would be available
as comptime booleans via `@import("builtin")` but they should not
be exposed that way.
With this change the downsides are:
* the option name of addExecutable and friends is `target` instead of
`resolved_target` matching the type name.
- upside: this does not break compatibility with existing build
scripts
* you likely end up seeing `target.result.cpu.arch` rather than
`target.cpu.arch`.
- upside: this is an improvement over `target.target.cpu.arch` which
it was before this commit.
- downside: `b.host.target` is now `b.host.result`.
Introduce the concept of "target query" and "resolved target". A target
query is what the user specifies, with some things left to default. A
resolved target has the default things discovered and populated.
In the future, std.zig.CrossTarget will be rename to std.Target.Query.
Introduces `std.Build.resolveTargetQuery` to get from one to the other.
The concept of `main_mod_path` is gone, no longer supported. You have to
put the root source file at the module root now.
* remove deprecated API
* update build.zig for the breaking API changes in this branch
* move std.Build.Step.Compile.BuildId to std.zig.BuildId
* add more options to std.Build.ExecutableOptions, std.Build.ObjectOptions,
std.Build.SharedLibraryOptions, std.Build.StaticLibraryOptions, and
std.Build.TestOptions.
* remove `std.Build.constructCMacro`. There is no use for this API.
* deprecate `std.Build.Step.Compile.defineCMacro`. Instead,
`std.Build.Module.addCMacro` is provided.
- remove `std.Build.Step.Compile.defineCMacroRaw`.
* deprecate `std.Build.Step.Compile.linkFrameworkNeeded`
- use `std.Build.Module.linkFramework`
* deprecate `std.Build.Step.Compile.linkFrameworkWeak`
- use `std.Build.Module.linkFramework`
* move more logic into `std.Build.Module`
* allow `target` and `optimize` to be `null` when creating a Module.
Along with other fields, those unspecified options will be inherited
from parent `Module` when inserted into an import table.
* the `target` field of `addExecutable` is now required. pass `b.host`
to get the host target.
