These cpp files reference SYS_* macros but do not explicitly include syscall.h as required.

diff '--color=auto' -ur a/src/mongo/util/concurrency/ticket_pool.cpp b/src/mongo/util/concurrency/ticket_pool.cpp
--- a/src/mongo/util/concurrency/ticket_pool.cpp	2026-05-13 19:17:03.000000000 -0400
+++ b/src/mongo/util/concurrency/ticket_pool.cpp	2026-05-29 12:44:21.118990277 -0400
@@ -34,7 +34,7 @@
 #include <ctime>
 #include <mutex>
 #include <string>
-// IWYU pragma: no_include "syscall.h"
+#include "syscall.h"
 
 
 #ifndef _WIN32
diff '--color=auto' -ur a/src/mongo/util/stacktrace_test.cpp b/src/mongo/util/stacktrace_test.cpp
--- a/src/mongo/util/stacktrace_test.cpp	2026-05-13 19:17:03.000000000 -0400
+++ b/src/mongo/util/stacktrace_test.cpp	2026-05-29 12:44:21.119199643 -0400
@@ -33,7 +33,7 @@
 // IWYU pragma: no_include "bits/types/stack_t.h"
 #include <fmt/format.h>
 #include <fmt/printf.h>  // IWYU pragma: keep
-// IWYU pragma: no_include "syscall.h"
+#include "syscall.h"
 // IWYU pragma: no_include "cxxabi.h"
 #include <algorithm>
 #include <array>
diff '--color=auto' -ur a/src/mongo/util/stacktrace_threads.cpp b/src/mongo/util/stacktrace_threads.cpp
--- a/src/mongo/util/stacktrace_threads.cpp	2026-05-13 19:17:03.000000000 -0400
+++ b/src/mongo/util/stacktrace_threads.cpp	2026-05-29 12:44:21.118737175 -0400
@@ -53,7 +53,7 @@
 #include <string>
 #include <utility>
 #include <vector>
-// IWYU pragma: no_include <syscall.h>
+#include <syscall.h>
 // IWYU pragma: no_include "bits/types/siginfo_t.h"
 
 #include "mongo/base/parse_number.h"