diff --git a/Makefile.in b/Makefile.in
index 68f79c0ad..8870f6cc0 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -89,7 +89,6 @@ datarootdir = @datarootdir@
 CFG_WITH_CCWARN = @CFG_WITH_CCWARN@
 CFG_WITH_DEFENV = @CFG_WITH_DEFENV@
 CFG_WITH_LONGTESTS = @CFG_WITH_LONGTESTS@
-CFG_WITH_THREADED = @CFG_WITH_THREADED@
 PACKAGE_VERSION = @PACKAGE_VERSION@
 
 #### End of system configuration section. ####
@@ -546,9 +545,6 @@ dist-file-list:
 	@echo $(wildcard $(DISTFILES))
 	@echo "end-dist-file-list:";  # Scripts look for this
 
-print-cfg-with-threaded:
-	@echo $(CFG_WITH_THREADED)
-
 ######################################################################
 # Distributions
 
diff --git a/configure.ac b/configure.ac
index e0c7b9983..de9d56c13 100644
--- a/configure.ac
+++ b/configure.ac
@@ -394,12 +394,17 @@ _MY_LDLIBS_CHECK_IFELSE(
    fi])
 AC_SUBST(CFG_LIBS)
 
-# Set CFG_WITH_THREADED if can support threading
-AC_MSG_CHECKING(whether $CXX supports Verilated threads)
-ACO_SAVE_CXXFLAGS="$CXXFLAGS"
-CXXFLAGS="$CXXFLAGS $CFG_CXXFLAGS_STD_NEWEST $CFG_CXXFLAGS_NO_UNUSED"
-AC_LINK_IFELSE(
-     [AC_LANG_PROGRAM([#include <thread>], [[ ]])],
+# Need C++11 at least
+#Alternative: AX_CXX_COMPILE_STDCXX([11])
+AC_DEFUN([_MY_CXX_CHECK_CXX_VER],
+   [# _MY_CXX_CHECK_CXX_VER(flag) -- Check if compiler runs C++11
+    # Set $_my_result
+    AC_LINK_IFELSE(
+     [AC_LANG_PROGRAM([#include <thread>
+#if (__cplusplus < 201103L)
+# error "Too old"
+#endif
+    ], [[ ]])],
      [_my_result=yes
       if test -s conftest.err; then
         if grep -e "$1" conftest.err >/dev/null; then
@@ -407,13 +412,18 @@ AC_LINK_IFELSE(
         fi
       fi],
      [_my_result=no])
-CFG_WITH_THREADED=$_my_result
-AC_SUBST(CFG_WITH_THREADED)
-AC_MSG_RESULT($CFG_WITH_THREADED)
-CXXFLAGS="$ACO_SAVE_CXXFLAGS"
+   ])
 
-# Check compiler flag
-if test "$CFG_WITH_THREADED" = "no" ; then
+AC_MSG_CHECKING(whether $CXX supports C++11)
+_MY_CXX_CHECK_CXX_VER()
+AC_MSG_RESULT($_my_result)
+if test "$_my_result" = "no" ; then
+   CXXFLAGS="$CXXFLAGS $CFG_CXXFLAGS_STD_NEWEST"
+   AC_MSG_CHECKING(whether $CXX supports C++11 with $CFG_CXXFLAGS_STD_NEWEST)
+   _MY_CXX_CHECK_CXX_VER()
+   AC_MSG_RESULT($_my_result)
+fi
+if test "$_my_result" = "no" ; then
    AC_MSG_NOTICE([[]])
    AC_MSG_ERROR([[the $CXX compiler appears to not support C++11.
 
diff --git a/include/verilatedos.h b/include/verilatedos.h
index 4ababb153..7ba4ff55c 100644
--- a/include/verilatedos.h
+++ b/include/verilatedos.h
@@ -122,7 +122,7 @@
 # if defined(_MSC_VER) && _MSC_VER >= 1900
 #  define VL_THREAD_LOCAL thread_local
 # elif defined(__GNUC__)
-#  if (__cplusplus < 201103L) && !defined(VL_THREADED_NO_C11_WARNING)
+#  if (__cplusplus < 201103L)
 #   error "VL_THREADED/--threads support requires C++-11 or newer only; use newer compiler"
 #  endif
 # else
diff --git a/test_regress/driver.pl b/test_regress/driver.pl
index d4b12ddb5..4e668eee6 100755
--- a/test_regress/driver.pl
+++ b/test_regress/driver.pl
@@ -2250,10 +2250,8 @@ sub cxx_version {
     return $_Cxx_Version;
 }
 
-our $_Cfg_With_Threaded;
 sub cfg_with_threaded {
-    $_Cfg_With_Threaded ||= `$ENV{MAKE} -C $ENV{VERILATOR_ROOT} -f Makefile print-cfg-with-threaded`;
-    return ($_Cfg_With_Threaded =~ /yes/i) ? 1:0;
+    return 1;  # C++11 now always required
 }
 
 sub tries {