Index: sapi/apache2handler/config.m4
===================================================================
--- sapi/apache2handler/config.m4	(revision 323592)
+++ sapi/apache2handler/config.m4	(working copy)
@@ -38,7 +38,6 @@
   APXS_BINDIR=`$APXS -q BINDIR`
   APXS_HTTPD=`$APXS -q SBINDIR`/`$APXS -q TARGET`
   APXS_CFLAGS=`$APXS -q CFLAGS`
-  APXS_MPM=`$APXS -q MPM_NAME`
   APU_BINDIR=`$APXS -q APU_BINDIR`
   APR_BINDIR=`$APXS -q APR_BINDIR`
 
@@ -117,8 +116,16 @@
     ;;
   esac
 
-  if test "$APXS_MPM" != "prefork" && test "$APXS_MPM" != "peruser" && test "$APXS_MPM" != "itk"; then
-    PHP_BUILD_THREAD_SAFE
+  if test "$APACHE_VERSION" -lt 2004001; then
+    APXS_MPM=`$APXS -q MPM_NAME`
+    if test "$APXS_MPM" != "prefork" && test "$APXS_MPM" != "peruser" && test "$APXS_MPM" != "itk"; then
+      PHP_BUILD_THREAD_SAFE
+    fi
+  else
+    APACHE_THREADED_MPM=`$APXS_HTTPD -V | grep 'threaded:.*yes'`
+    if test -n "$APACHE_THREADED_MPM"; then
+      PHP_BUILD_THREAD_SAFE
+    fi
   fi
   AC_MSG_RESULT(yes)
   PHP_SUBST(APXS)
Index: sapi/apache2filter/config.m4
===================================================================
--- sapi/apache2filter/config.m4	(revision 323592)
+++ sapi/apache2filter/config.m4	(working copy)
@@ -39,7 +39,6 @@
   APXS_BINDIR=`$APXS -q BINDIR`
   APXS_HTTPD=`$APXS -q SBINDIR`/`$APXS -q TARGET`
   APXS_CFLAGS=`$APXS -q CFLAGS`
-  APXS_MPM=`$APXS -q MPM_NAME`
   APU_BINDIR=`$APXS -q APU_BINDIR`
   APR_BINDIR=`$APXS -q APR_BINDIR`
 
@@ -118,8 +117,16 @@
     ;;
   esac
 
-  if test "$APXS_MPM" != "prefork" && test "$APXS_MPM" != "peruser"; then
-    PHP_BUILD_THREAD_SAFE
+  if test "$APACHE_VERSION" -lt 2004001; then
+    APXS_MPM=`$APXS -q MPM_NAME`
+    if test "$APXS_MPM" != "prefork" && test "$APXS_MPM" != "peruser" && test "$APXS_MPM" != "itk"; then
+      PHP_BUILD_THREAD_SAFE
+    fi
+  else
+    APACHE_THREADED_MPM=`$APXS_HTTPD -V | grep 'threaded:.*yes'`
+    if test -n "$APACHE_THREADED_MPM"; then
+      PHP_BUILD_THREAD_SAFE
+    fi
   fi
   AC_MSG_RESULT(yes)
   PHP_SUBST(APXS)
Index: configure.in
===================================================================
--- configure.in	(revision 323592)
+++ configure.in	(working copy)
@@ -1550,6 +1550,21 @@
 X
   fi
 
+    if test "$PHP_SAPI" = "apache2handler" || test "$PHP_SAPI" = "apache2filter"; then
+      if test "$APACHE_VERSION" -ge 2004001; then
+        if test -z "$APACHE_THREADED_MPM"; then
+cat <<X
++--------------------------------------------------------------------+
+|                        *** WARNING ***                             |
+|                                                                    |
+| You have built PHP for Apache's current non-threaded MPM.          |
+| If you change Apache to use a threaded MPM you must reconfigure    |
+| PHP with --enable-maintainer-zts                                   |
+X
+        fi
+      fi
+    fi
+
   # Warn about linking Apache with libpthread if oci8 extension is enabled on linux.
   if test "$PHP_OCI8" != "no"; then
     if test "$PHP_SAPI" = "apache"; then