earcut: update to latest Zig build API

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

libs/earcut/build.zig

@@ -1,25 +1,40 @@
 const std = @import("std");
 
-pub fn build(b: *std.build.Builder) void {
-    const mode = b.standardReleaseOptions();
-    const lib = b.addStaticLibrary("earcut", "src/main.zig");
-    lib.setBuildMode(mode);
+pub fn build(b: *std.Build) void {
+    const optimize = b.standardOptimizeOption(.{});
+    const target = b.standardTargetOptions(.{});
+    const lib = b.addStaticLibrary(.{
+        .name = "earcut",
+        .root_source_file = .{ .path = "src/main.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
     lib.install();
 
-    var main_tests = b.addTest("src/main.zig");
-    main_tests.setBuildMode(mode);
+    const main_tests = b.addTest(.{
+        .name = "earcut-tests",
+        .kind = .test_exe,
+        .root_source_file = .{ .path = "src/main.zig" },
+        .target = target,
+        .optimize = optimize,
+    });
 
     const test_step = b.step("test", "Run library tests");
     test_step.dependOn(&main_tests.step);
 
-    _ = pkg;
+    _ = module(b);
 }
 
-pub const pkg = std.build.Pkg{
-    .name = "earcut",
-    .source = .{ .path = thisDir() ++ "/src/main.zig" },
-};
-
-fn thisDir() []const u8 {
-    return std.fs.path.dirname(@src().file) orelse ".";
+pub fn module(b: *std.Build) *std.build.Module {
+    return b.createModule(.{
+        .source_file = .{ .path = sdkPath("/src/main.zig") },
+    });
+}
+
+fn sdkPath(comptime suffix: []const u8) []const u8 {
+    if (suffix[0] != '/') @compileError("suffix must be an absolute path");
+    return comptime blk: {
+        const root_dir = std.fs.path.dirname(@src().file) orelse ".";
+        break :blk root_dir ++ suffix;
+    };
 }