build: remove App (not CoreApp)

This removes the old `App` builder, leaving only `CoreApp` as something
to resolve/remove.

Helps hexops/mach#1186

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>

build.zig

@@ -316,79 +316,6 @@ pub fn build(b: *std.Build) !void {
     }
 }
 
-pub const App = struct {
-    b: *std.Build,
-    mach_builder: *std.Build,
-    name: []const u8,
-    compile: *std.Build.Step.Compile,
-    install: *std.Build.Step.InstallArtifact,
-    run: *std.Build.Step.Run,
-    platform: CoreApp.Platform,
-    core: CoreApp,
-
-    pub fn init(
-        app_builder: *std.Build,
-        options: struct {
-            name: []const u8,
-            src: []const u8,
-            target: std.Build.ResolvedTarget,
-            optimize: std.builtin.OptimizeMode,
-            custom_entrypoint: ?[]const u8 = null,
-            deps: ?[]const std.Build.Module.Import = null,
-            res_dirs: ?[]const []const u8 = null,
-            watch_paths: ?[]const []const u8 = null,
-            mach_builder: ?*std.Build = null,
-            mach_mod: ?*std.Build.Module = null,
-        },
-    ) !App {
-        const mach_builder = options.mach_builder orelse app_builder.dependency("mach", .{
-            .target = options.target,
-            .optimize = options.optimize,
-        }).builder;
-        const mach_mod = options.mach_mod orelse app_builder.dependency("mach", .{
-            .target = options.target,
-            .optimize = options.optimize,
-        }).module("mach");
-
-        var deps = std.ArrayList(std.Build.Module.Import).init(app_builder.allocator);
-        if (options.deps) |v| try deps.appendSlice(v);
-        try deps.append(.{ .name = "mach", .module = mach_mod });
-
-        const app = try CoreApp.init(app_builder, mach_builder, .{
-            .name = options.name,
-            .src = options.src,
-            .target = options.target,
-            .optimize = options.optimize,
-            .custom_entrypoint = options.custom_entrypoint,
-            .deps = deps.items,
-            .res_dirs = options.res_dirs,
-            .watch_paths = options.watch_paths,
-            .mach_mod = mach_mod,
-        });
-        return .{
-            .core = app,
-            .b = app.b,
-            .mach_builder = mach_builder,
-            .name = app.name,
-            .compile = app.compile,
-            .install = app.install,
-            .run = app.run,
-            .platform = app.platform,
-        };
-    }
-
-    pub fn link(app: *const App) !void {
-        // TODO: basisu support in wasm
-        if (app.platform != .web) {
-            app.compile.linkLibrary(app.mach_builder.dependency("mach_basisu", .{
-                .target = app.compile.root_module.resolved_target.?,
-                .optimize = app.compile.root_module.optimize.?,
-            }).artifact("mach-basisu"));
-            addPaths(&app.compile.root_module);
-        }
-    }
-};
-
 pub const CoreApp = struct {
     b: *std.Build,
     name: []const u8,