Default to ucs2 when no argument to --enable-unicode is specified.

configure

 #! /bin/sh
 
-# From configure.in Revision: 1.221 
+# From configure.in Revision: 1.222 
 
 # Guess values for system-dependent variables and create Makefiles.
 # Generated automatically using autoconf version 2.13 
@@ -6579,12 +6579,8 @@ fi
 
 if test $enable_unicode = yes
 then
-  # Let Py_UNICODE size depend on wchar_t size
-  case  "$ac_cv_sizeof_wchar_t" in
-  2) enable_unicode="ucs2";;
-  4) enable_unicode="ucs4";;
-  *) enable_unicode="ucs4";; # default to UCS-4
-  esac
+  # Without any arguments, Py_UNICODE defaults to two-byte mode
+  enable_unicode="ucs2"
 fi
 
 case "$enable_unicode" in
@@ -6643,14 +6639,14 @@ fi
 
 # check for endianness
 echo $ac_n "checking whether byte ordering is bigendian""... $ac_c" 1>&6
-echo "configure:6647: checking whether byte ordering is bigendian" >&5
+echo "configure:6643: checking whether byte ordering is bigendian" >&5
 if eval "test \"`echo '$''{'ac_cv_c_bigendian'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   ac_cv_c_bigendian=unknown
 # See if sys/param.h defines the BYTE_ORDER macro.
 cat > conftest.$ac_ext <<EOF
-#line 6654 "configure"
+#line 6650 "configure"
 #include "confdefs.h"
 #include <sys/types.h>
 #include <sys/param.h>
@@ -6661,11 +6657,11 @@ int main() {
 #endif
 ; return 0; }
 EOF
-if { (eval echo configure:6665: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
+if { (eval echo configure:6661: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
   rm -rf conftest*
   # It does; now see whether it defined to BIG_ENDIAN or not.
 cat > conftest.$ac_ext <<EOF
-#line 6669 "configure"
+#line 6665 "configure"
 #include "confdefs.h"
 #include <sys/types.h>
 #include <sys/param.h>
@@ -6676,7 +6672,7 @@ int main() {
 #endif
 ; return 0; }
 EOF
-if { (eval echo configure:6680: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
+if { (eval echo configure:6676: \"$ac_compile\") 1>&5; (eval $ac_compile) 2>&5; }; then
   rm -rf conftest*
   ac_cv_c_bigendian=yes
 else
@@ -6696,7 +6692,7 @@ if test "$cross_compiling" = yes; then
     { echo "configure: error: can not run test program while cross compiling" 1>&2; exit 1; }
 else
   cat > conftest.$ac_ext <<EOF
-#line 6700 "configure"
+#line 6696 "configure"
 #include "confdefs.h"
 main () {
   /* Are we little or big endian?  From Harbison&Steele.  */
@@ -6709,7 +6705,7 @@ main () {
   exit (u.c[sizeof (long) - 1] == 1);
 }
 EOF
-if { (eval echo configure:6713: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext} && (./conftest; exit) 2>/dev/null
+if { (eval echo configure:6709: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext} && (./conftest; exit) 2>/dev/null
 then
   ac_cv_c_bigendian=no
 else
@@ -6736,7 +6732,7 @@ fi
 # Check whether right shifting a negative integer extends the sign bit
 # or fills with zeros (like the Cray J90, according to Tim Peters).
 echo $ac_n "checking whether right shift extends the sign bit""... $ac_c" 1>&6
-echo "configure:6740: checking whether right shift extends the sign bit" >&5
+echo "configure:6736: checking whether right shift extends the sign bit" >&5
 if eval "test \"`echo '$''{'ac_cv_rshift_extends_sign'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
@@ -6745,7 +6741,7 @@ if test "$cross_compiling" = yes; then
     { echo "configure: error: can not run test program while cross compiling" 1>&2; exit 1; }
 else
   cat > conftest.$ac_ext <<EOF
-#line 6749 "configure"
+#line 6745 "configure"
 #include "confdefs.h"
 
 int main()
@@ -6754,7 +6750,7 @@ int main()
 }
 
 EOF
-if { (eval echo configure:6758: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext} && (./conftest; exit) 2>/dev/null
+if { (eval echo configure:6754: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext} && (./conftest; exit) 2>/dev/null
 then
   ac_cv_rshift_extends_sign=yes
 else
@@ -6779,13 +6775,13 @@ fi
 
 # check for getc_unlocked and related locking functions
 echo $ac_n "checking for getc_unlocked() and friends""... $ac_c" 1>&6
-echo "configure:6783: checking for getc_unlocked() and friends" >&5
+echo "configure:6779: checking for getc_unlocked() and friends" >&5
 if eval "test \"`echo '$''{'ac_cv_have_getc_unlocked'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   
 cat > conftest.$ac_ext <<EOF
-#line 6789 "configure"
+#line 6785 "configure"
 #include "confdefs.h"
 #include <stdio.h>
 int main() {
@@ -6797,7 +6793,7 @@ int main() {
 
 ; return 0; }
 EOF
-if { (eval echo configure:6801: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
+if { (eval echo configure:6797: \"$ac_link\") 1>&5; (eval $ac_link) 2>&5; } && test -s conftest${ac_exeext}; then
   rm -rf conftest*
   ac_cv_have_getc_unlocked=yes
 else
@@ -6826,12 +6822,12 @@ cat >> confdefs.h <<\EOF
 #endif
 EOF
 echo $ac_n "checking for socklen_t""... $ac_c" 1>&6
-echo "configure:6830: checking for socklen_t" >&5
+echo "configure:6826: checking for socklen_t" >&5
 if eval "test \"`echo '$''{'ac_cv_type_socklen_t'+set}'`\" = set"; then
   echo $ac_n "(cached) $ac_c" 1>&6
 else
   cat > conftest.$ac_ext <<EOF
-#line 6835 "configure"
+#line 6831 "configure"
 #include "confdefs.h"
 #include <sys/types.h>
 #if STDC_HEADERS
@@ -6880,7 +6876,7 @@ done
 
 SRCDIRS="Parser Grammar Objects Python Modules"
 echo $ac_n "checking for build directories""... $ac_c" 1>&6
-echo "configure:6884: checking for build directories" >&5
+echo "configure:6880: checking for build directories" >&5
 for dir in $SRCDIRS; do
     if test ! -d $dir; then
         mkdir $dir

configure.in

@@ -1590,12 +1590,8 @@ AC_ARG_ENABLE(unicode,
 
 if test $enable_unicode = yes
 then
-  # Let Py_UNICODE size depend on wchar_t size
-  case  "$ac_cv_sizeof_wchar_t" in
-  2) enable_unicode="ucs2";;
-  4) enable_unicode="ucs4";;
-  *) enable_unicode="ucs4";; # default to UCS-4
-  esac
+  # Without any arguments, Py_UNICODE defaults to two-byte mode
+  enable_unicode="ucs2"
 fi
 
 case "$enable_unicode" in