code: update os.waitpid usage for breaking change

 river/Output.zig        | 4 ++--
 river/command/spawn.zig | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/river/Output.zig b/river/Output.zig
index 21ecfb2..d19c8ec 100644
--- a/river/Output.zig
+++ b/river/Output.zig
@@ -242,8 +242,8 @@ fn layoutExternal(self: *Self, visible_count: u32) !void {
     defer stdout.close();
 
     // TODO abort after a timeout
-    const status = std.os.waitpid(pid, 0);
-    if (!std.os.WIFEXITED(status) or std.os.WEXITSTATUS(status) != 0)
+    const ret = std.os.waitpid(pid, 0);
+    if (!std.os.WIFEXITED(ret.status) or std.os.WEXITSTATUS(ret.status) != 0)
         return LayoutError.BadExitCode;
 
     const buffer = try stdout.inStream().readAllAlloc(&arena.allocator, 1024);
diff --git a/river/command/spawn.zig b/river/command/spawn.zig
index 8e1bdfe..101e377 100644
--- a/river/command/spawn.zig
+++ b/river/command/spawn.zig
@@ -55,9 +55,9 @@ pub fn spawn(
     }
 
     // Wait the intermediate child.
-    const status = std.os.waitpid(pid, 0);
-    if (!std.os.WIFEXITED(status) or
-        (std.os.WIFEXITED(status) and std.os.WEXITSTATUS(status) != 0))
+    const ret = std.os.waitpid(pid, 0);
+    if (!std.os.WIFEXITED(ret.status) or
+        (std.os.WIFEXITED(ret.status) and std.os.WEXITSTATUS(ret.status) != 0))
     {
         out.* = try std.fmt.allocPrint(allocator, "fork/execve failed", .{});
         return Error.Other;