diff -ru iperf-3.17.1.orig/src/iperf_api.h iperf-3.17.1/src/iperf_api.h
--- iperf-3.17.1.orig/src/iperf_api.h	2024-05-13 20:40:55.000000000 +0200
+++ iperf-3.17.1/src/iperf_api.h	2024-07-02 20:05:03.818580250 +0200
@@ -44,7 +44,7 @@
 #include <stdatomic.h>
 #else
 #warning "No <stdatomic.h> available"
-typedef u_int64_t atomic_uint_fast64_t;
+typedef uint64_t atomic_uint_fast64_t;
 #endif // HAVE_STDATOMIC_H
 
 struct iperf_test;
diff -ru iperf-3.17.1.orig/src/main.c iperf-3.17.1/src/main.c
--- iperf-3.17.1.orig/src/main.c	2024-05-13 20:40:55.000000000 +0200
+++ iperf-3.17.1/src/main.c	2024-07-02 20:04:06.908582670 +0200
@@ -65,15 +65,6 @@
      * know how to check this on GCC. GCC on CentOS 7 / RHEL 7 is the
      * targeted use case for these check.
      */
-#ifndef HAVE_STDATOMIC_H
-#ifdef __GNUC__
-    if (! __atomic_always_lock_free (sizeof (u_int64_t), 0)) {
-#endif // __GNUC__
-        fprintf(stderr, "Warning: Cannot guarantee lock-free operation with 64-bit data types\n");
-#ifdef __GNUC__
-    }
-#endif // __GNUC__
-#endif // HAVE_STDATOMIC_H
 
     // XXX: Setting the process affinity requires root on most systems.
     //      Is this a feature we really need?
Only in iperf-3.17.1/src: main.c.orig