fix: pthread differs on linux vs macos (#65)

src/clock.zig

@@ -37,11 +37,7 @@ const Fabric = struct {
         allocator.destroy(self);
     }
     fn loop(self: *Fabric) void {
-        const priority: pthread.sched_param = .{
-            .sched_priority = 90,
-            .__opaque = undefined,
-        };
-        _ = pthread.pthread_setschedparam(pthread.pthread_self(), pthread.SCHED_FIFO, &priority);
+        pthread.set_priority(90);
         while (!self.quit) {
             self.do_tick();
             self.time += self.tick;

src/main.zig

@@ -49,11 +49,7 @@ pub fn main() !void {
     defer if (option) |_| create.deinit();
     while (go_again) {
         try print_version();
-        const priority: pthread.sched_param = .{
-            .sched_priority = 99,
-            .__opaque = undefined,
-        };
-        _ = pthread.pthread_setschedparam(pthread.pthread_self(), pthread.SCHED_FIFO, &priority);
+        pthread.set_priority(99);
 
         const path = try std.fs.path.join(allocator, &.{ location, "..", "share", "seamstress", "lua" });
         defer allocator.free(path);

src/metros.zig

@@ -132,11 +132,7 @@ fn loop(self: *Metro, pid: *Thread) void {
     self.status_lock.lock();
     self.status = Status.Running;
     self.status_lock.unlock();
-    const priority: pthread.sched_param = .{
-        .sched_priority = 90,
-        .__opaque = undefined,
-    };
-    _ = pthread.pthread_setschedparam(pthread.pthread_self(), pthread.SCHED_FIFO, &priority);
+    pthread.set_priority(90);
     while (!pid.quit) {
         self.wait();
         self.stage_lock.lock();

src/pthread.zig

@@ -1 +1,16 @@
-pub usingnamespace @cImport(@cInclude("pthread.h"));
+const c = @cImport(@cInclude("pthread.h"));
+const builtin = @import("builtin");
+
+pub fn set_priority(priority: u8) void {
+    const priority_struct: c.sched_param = switch (comptime builtin.os.tag) {
+        .linux => .{
+            .sched_priority = priority,
+        },
+        .macos => .{
+            .sched_priority = priority,
+            .__opaque = undefined,
+        },
+        else => return,
+    };
+    _ = c.pthread_setschedparam(c.pthread_self(), c.SCHED_FIFO, &priority_struct);
+}