[WIP] Darwin: FSWatch API

CMakeLists.txt

@@ -466,6 +466,9 @@ set(ZIG_STD_FILES
     "event/lock.zig"
     "event/locked.zig"
     "event/loop.zig"
+    "event/loop/darwin.zig"
+    "event/loop/linux.zig"
+    "event/loop/windows.zig"
     "event/rwlock.zig"
     "event/rwlocked.zig"
     "event/tcp.zig"

src/link.cpp

@@ -921,6 +921,12 @@ static void construct_linker_job_macho(LinkJob *lj) {
         zig_panic("TODO");
     }
 
+    // Always include CoreFoundation
+    // Is There a Better Way? 
+    // https://github.com/ziglang/zig/issues/1349
+    lj->args.append("-framework");
+    lj->args.append("CoreFoundation");
+
     for (size_t i = 0; i < g->darwin_frameworks.length; i += 1) {
         lj->args.append("-framework");
         lj->args.append(buf_ptr(g->darwin_frameworks.at(i)));

std/c/darwin.zig

@@ -1,3 +1,7 @@
+pub const CFRunLoop = @cImport({
+    @cInclude("CoreFoundation/CFRunLoop.h");
+});
+
 extern "c" fn __error() *c_int;
 pub extern "c" fn _NSGetExecutablePath(buf: [*]u8, bufsize: *u32) c_int;
 

std/event.zig

@@ -1,12 +1,22 @@
+const builtin = @import("builtin");
 pub const Channel = @import("event/channel.zig").Channel;
 pub const Future = @import("event/future.zig").Future;
 pub const Group = @import("event/group.zig").Group;
 pub const Lock = @import("event/lock.zig").Lock;
 pub const Locked = @import("event/locked.zig").Locked;
 pub const RwLock = @import("event/rwlock.zig").RwLock;
 pub const RwLocked = @import("event/rwlocked.zig").RwLocked;
-pub const Loop = @import("event/loop.zig").Loop;
-pub const fs = @import("event/fs.zig");
+pub const Loop = switch (builtin.os) {
+    builtin.Os.linux,
+    builtin.Os.macosx,
+    builtin.Os.windows => @import("event/loop.zig").Loop,
+    else => @import("empty.zig"),
+};
+pub const fs = switch (builtin.os) {
+    builtin.Os.linux,
+    builtin.Os.macosx => @import("event/fs.zig"),
+    else => @import("empty.zig"),
+};
 pub const tcp = @import("event/tcp.zig");
 
 test "import event tests" {

std/event/fs.zig

@@ -531,9 +531,9 @@ pub fn Watch(comptime V: type) type {
                     os.linux.EINVAL => unreachable,
                     os.linux.EFAULT => unreachable,
                     os.linux.EAGAIN => {
-                        (await (async loop.linuxWaitFd(
+                        (await (async loop.waitEvHandle(
                             inotify_fd,
-                            os.linux.EPOLLET | os.linux.EPOLLIN,
+                            event.Loop.EventFlags.READ,
                         ) catch unreachable)) catch |err| {
                             const transformed_err = switch (err) {
                                 error.InvalidFileDescriptor => unreachable,