mitchell's touchups

- benchmark: avoid buffers to avoid a memcpy
- build: keep frame pointers on macOS. There was some debug changes from
  Zig 0.15 and this helps. Also, Apple actually requires/expects x29 to
  always be a frame pointer.
- build/macos: force libSystem symbols instead of compiler-rt
- global: add InitOpts.tool so that ghostty-gen/bench can parse their
  own actions in `+action`
- quirks: provide our own vectorized memset. see the comment for more
  details why.
- synthetic: fix UB by accessing global.io before it was initialized
- terminal/hash_map: force inline for unique repr types. Zig 0.15
  inlined and 0.16 doesn't, measured a huge slowdown in hyperlink
  benchmarks.
- terminal: add explicit `@Vector` usage for storing a run of identical cells
  as well as for scanning printable cells. This auto-vectorized in Zig
  0.15 but not in Zig 0.16. This produces the same assembly.
- unicode: properties and LUT need power-of-two backing integer to avoid
  bad LLVM codegen

src/benchmark/TerminalStream.zig

@@ -113,8 +113,10 @@ fn step(ptr: *anyopaque) Benchmark.Error!void {
     // aren't currently IO bound.
     const f = self.data_f orelse return;
 
-    var read_buf: [64 * 1024]u8 align(std.atomic.cache_line) = undefined;
-    var f_reader = f.reader(global.io(), &read_buf);
+    // Unbuffered: readSliceShort below reads directly into `buf`,
+    // avoiding a per-chunk memcpy through an intermediate reader
+    // buffer that would pollute the measurement.
+    var f_reader = f.reader(global.io(), &.{});
     const r = &f_reader.interface;
 
     // This buffer size matches the read buffer size used by the

src/benchmark/cli.zig

@@ -46,7 +46,7 @@ pub const Action = enum {
 
 /// An entrypoint for the benchmark CLI.
 pub fn main(init: std.process.Init) !void {
-    try global.init(.{ .main = init });
+    try global.init(.{ .tool = init });
     const alloc = std.heap.c_allocator;
     const action_ = try cli.action.detectArgs(Action, alloc, init.minimal.args);
     const action = action_ orelse return error.NoAction;