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.
These arrays don't really all have an upper bound of 16; in fact they
have different upper bounds. Presumably the reason 16 was used for all
of them was to avoid code bloat with BoundedArray. Well, now even more
code bloat has been eliminated because now it's using
`ArrayList([]const u8)` which is certainly instantiated elsewhere.
Furthermore, the different corrected upper bounds can be specified at
each instance of the array list.
I consider this change to be neutral. It inlines a bit of logic that
previously was abstracted, however, it also eliminates an instance of
`catch unreachable` as well as a clumsy failed pop / append in favor of
writing directly to the appropriate array element.
This simplifies the logic. For example, in generateExactWidthType, it no
longer has to save a previous length and then use defer to reset the
length after mutating it.
