diff --git a/PC/VC6/rt.bat b/PC/VC6/rt.bat
index a9eadd7..dfdea67 100755
--- a/PC/VC6/rt.bat
+++ b/PC/VC6/rt.bat
@@ -31,11 +31,11 @@
 @if "%_qmode%"=="yes" goto Qmode
 @echo Deleting .pyc/.pyo files ...
 @%_exe% rmpyc.py
-%_exe% %_dashO% -E ../../lib/test/regrtest.py %1 %2 %3 %4 %5 %6 %7 %8 %9
+%_exe% %_dashO% -E -tt ../../lib/test/regrtest.py %1 %2 %3 %4 %5 %6 %7 %8 %9
 @echo About to run again without deleting .pyc/.pyo first:
 @pause
 :Qmode
-%_exe% %_dashO% -E ../../lib/test/regrtest.py %1 %2 %3 %4 %5 %6 %7 %8 %9
+%_exe% %_dashO% -E -tt ../../lib/test/regrtest.py %1 %2 %3 %4 %5 %6 %7 %8 %9
 @set _exe=
 @set _qmode=
 @set _dashO=
diff --git a/PC/VS7.1/rt.bat b/PC/VS7.1/rt.bat
index ba1d090..29801d2 100755
--- a/PC/VS7.1/rt.bat
+++ b/PC/VS7.1/rt.bat
@@ -34,7 +34,7 @@
 if "%1"=="-q" (set qmode=yes)    & shift & goto CheckOpts
 if "%1"=="-d" (set exe=python_d) & shift & goto CheckOpts
 
-set cmd=%exe% %dashO% -E ../../lib/test/regrtest.py %1 %2 %3 %4 %5 %6 %7 %8 %9
+set cmd=%exe% %dashO% -E -tt ../../lib/test/regrtest.py %1 %2 %3 %4 %5 %6 %7 %8 %9
 if defined qmode goto Qmode
 
 echo Deleting .pyc/.pyo files ...
diff --git a/PC/VS8.0/rt.bat b/PC/VS8.0/rt.bat
index d691cbd..90fd794 100644
--- a/PC/VS8.0/rt.bat
+++ b/PC/VS8.0/rt.bat
@@ -34,7 +34,7 @@
 if "%1"=="-q" (set qmode=yes)    & shift & goto CheckOpts
 if "%1"=="-d" (set exe=python_d) & shift & goto CheckOpts
 
-set cmd=%exe% %dashO% -E ../../lib/test/regrtest.py %1 %2 %3 %4 %5 %6 %7 %8 %9
+set cmd=%exe% %dashO% -E -tt ../../lib/test/regrtest.py %1 %2 %3 %4 %5 %6 %7 %8 %9
 if defined qmode goto Qmode
 
 echo Deleting .pyc/.pyo files ...
diff --git a/PC/os2emx/Makefile b/PC/os2emx/Makefile
index 10cadf9..a2947a7 100644
--- a/PC/os2emx/Makefile
+++ b/PC/os2emx/Makefile
@@ -666,7 +666,7 @@
 # the test target
 test:
 	-find ../../Lib -name "*.py[co]" -exec rm {} ";"
-	-./python -E ../../lib/test/regrtest.py -l -u "network"
-	./python -E ../../lib/test/regrtest.py -l -u "network"
+	-./python -E -tt ../../lib/test/regrtest.py -l -u "network"
+	./python -E -tt ../../lib/test/regrtest.py -l -u "network"
 
 -include $(OUTBASE)python.dep
diff --git a/PC/os2emx/python26.def b/PC/os2emx/python26.def
index 3cdb44a..8bc91c8 100644
--- a/PC/os2emx/python26.def
+++ b/PC/os2emx/python26.def
@@ -49,6 +49,7 @@
   "PyParser_Delete"
 
 ; From python26_s.lib(parsetok)
+  "Py_TabcheckFlag"
   "PyParser_ParseString"
   "PyParser_ParseStringFlagsFilename"
   "PyParser_ParseFile"
diff --git a/PC/os2vacpp/python.def b/PC/os2vacpp/python.def
index 2b2d6e1..55a17d7 100644
--- a/PC/os2vacpp/python.def
+++ b/PC/os2vacpp/python.def
@@ -61,6 +61,7 @@
                Py_InteractiveFlag
                Py_NoSiteFlag
                Py_OptimizeFlag
+               Py_TabcheckFlag
                Py_UseClassExceptionsFlag
                Py_VerboseFlag
                _PyImport_Filetab