diff --git a/Misc/NEWS b/Misc/NEWS
index df257f5a3f5..c1162ed640f 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -34,6 +34,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #12372: POSIX semaphores are broken on AIX: don't use them.
+
 - Issue #12571: Add a plat-linux3 directory mirroring the plat-linux2
   directory, so that "import DLFCN" and other similar imports work on
   Linux 3.0.
diff --git a/configure b/configure
index 36723f614ad..23664e83461 100755
--- a/configure
+++ b/configure
@@ -8868,7 +8868,7 @@ $as_echo "#define _POSIX_THREADS 1" >>confdefs.h
 
       # Bug 662787: Using semaphores causes unexplicable hangs on Solaris 8.
       case  $ac_sys_system/$ac_sys_release in
-  SunOS/5.6)
+      SunOS/5.6)
 $as_echo "#define HAVE_PTHREAD_DESTRUCTOR 1" >>confdefs.h
 
 		       ;;
@@ -8876,14 +8876,10 @@ $as_echo "#define HAVE_PTHREAD_DESTRUCTOR 1" >>confdefs.h
 $as_echo "#define HAVE_BROKEN_POSIX_SEMAPHORES 1" >>confdefs.h
 
 		       ;;
-      AIX/5)
+      AIX/*)
 $as_echo "#define HAVE_BROKEN_POSIX_SEMAPHORES 1" >>confdefs.h
 
 		       ;;
-      AIX/6)
-$as_echo "#define HAVE_BROKEN_POSIX_SEMAPHORES 1" >>confdefs.h
-
-                      ;;
       esac
 
       { $as_echo "$as_me:${as_lineno-$LINENO}: checking if PTHREAD_SCOPE_SYSTEM is supported" >&5
diff --git a/configure.in b/configure.in
index 8e89c8fc368..de743ca47ba 100644
--- a/configure.in
+++ b/configure.in
@@ -2239,18 +2239,15 @@ if test "$posix_threads" = "yes"; then
 
       # Bug 662787: Using semaphores causes unexplicable hangs on Solaris 8.
       case  $ac_sys_system/$ac_sys_release in
-  SunOS/5.6) AC_DEFINE(HAVE_PTHREAD_DESTRUCTOR, 1,
+      SunOS/5.6) AC_DEFINE(HAVE_PTHREAD_DESTRUCTOR, 1,
                        [Defined for Solaris 2.6 bug in pthread header.])
 		       ;;
       SunOS/5.8) AC_DEFINE(HAVE_BROKEN_POSIX_SEMAPHORES, 1,
 		       [Define if the Posix semaphores do not work on your system])
 		       ;;
-      AIX/5) AC_DEFINE(HAVE_BROKEN_POSIX_SEMAPHORES, 1,
+      AIX/*) AC_DEFINE(HAVE_BROKEN_POSIX_SEMAPHORES, 1,
 		       [Define if the Posix semaphores do not work on your system])
 		       ;;
-      AIX/6) AC_DEFINE(HAVE_BROKEN_POSIX_SEMAPHORES, 1,
-                      Define if the Posix semaphores do not work on your system)
-                      ;;
       esac
 
       AC_MSG_CHECKING(if PTHREAD_SCOPE_SYSTEM is supported)