diff --git a/configure b/configure
index fe6c820..0440545 100755
--- a/configure
+++ b/configure
@@ -8296,6 +8296,8 @@
 # Check whether --with-system_expat was given.
 if test "${with_system_expat+set}" = set; then :
   withval=$with_system_expat;
+else
+  with_system_expat="no"
 fi
 
 
@@ -8309,6 +8311,8 @@
 # Check whether --with-system_ffi was given.
 if test "${with_system_ffi+set}" = set; then :
   withval=$with_system_ffi;
+else
+  with_system_ffi="no"
 fi
 
 
diff --git a/configure.in b/configure.in
index 3a87ff1..8f828de 100644
--- a/configure.in
+++ b/configure.in
@@ -2087,14 +2087,18 @@
 # Check for use of the system expat library
 AC_MSG_CHECKING(for --with-system-expat)
 AC_ARG_WITH(system_expat,
-            AS_HELP_STRING([--with-system-expat], [build pyexpat module using an installed expat library]))
+            AS_HELP_STRING([--with-system-expat], [build pyexpat module using an installed expat library]),
+            [],
+            [with_system_expat="no"])
 
 AC_MSG_RESULT($with_system_expat)
 
 # Check for use of the system libffi library
 AC_MSG_CHECKING(for --with-system-ffi)
 AC_ARG_WITH(system_ffi,
-            AS_HELP_STRING([--with-system-ffi], [build _ctypes module using an installed ffi library]))
+            AS_HELP_STRING([--with-system-ffi], [build _ctypes module using an installed ffi library]),
+            [],
+            [with_system_ffi="no"])
 
 if test "$with_system_ffi" = "yes" && test -n "$PKG_CONFIG"; then
     LIBFFI_INCLUDEDIR="`"$PKG_CONFIG" libffi --cflags-only-I 2>/dev/null | sed -e 's/^-I//;s/ *$//'`"