diff --git a/m4/acx_pthread.m4 b/m4/acx_pthread.m4
index a67bb1a22ed..4e92b4e2214 100644
--- a/m4/acx_pthread.m4
+++ b/m4/acx_pthread.m4
@@ -80,7 +80,7 @@ fi
 # which indicates that we try without any flags at all, and "pthread-config"
 # which is a program returning the flags for the Pth emulation library.
 
-acx_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
+acx_pthread_flags="pthreads pthread none -Kthread -kthread lthread -pthread -pthreads -mthreads --thread-safe -mt pthread-config"
 
 # The ordering *is* (sometimes) important.  Some notes on the
 # individual items follow: