--- a/configure	Mon Jun 17 20:37:47 2013 +0100
+++ b/configure	Wed Jun 19 09:30:30 2013 -0600
@@ -1968,7 +1968,8 @@
                           loaded libraries (Dynamic Shared Objects).
   --with-bignum=TYPE      Compile in support for bignums, ratios, or bigfloats
                           using library support. TYPE must be one of "gmp"
-                          (for GNU MP), "mp" (for BSD MP), or "no" (disabled).
+                          (for GNU MP), "mpir" (for MPIR), "mp" (for BSD MP),
+                          or "no" (disabled).
 
 Platform Specific options
 -------------------------
@@ -5178,14 +5179,14 @@
   enableval="$with_bignum"
   withval="$with_bignum"
   _bignum_bogus=yes
- for x in no gmp mp ; do
+ for x in no gmp mpir mp ; do
    if test $x = $with_bignum ; then
 	_bignum_bogus=no
    fi
  done
  if test "$_bignum_bogus" = "yes" ; then
 	(echo "$progname: Usage error:"
-echo " " "The --with-bignum option must have one of these values: \`no',\`gmp',\`mp'."
+echo " " "The --with-bignum option must have one of these values: \`no',\`gmp',\`mpir',\`mp'."
 echo "  Use \`$progname --help' to show usage.") >&2 && exit 1
  fi
 unset _bignum_bogus
@@ -20779,6 +20780,62 @@
   else
     { echo "Error:" "Required GMP numeric support cannot be provided." >&2; exit 1; }
   fi
+elif test "$with_bignum" = "mpir"; then
+  ac_fn_c_check_header_mongrel "$LINENO" "mpir.h" "ac_cv_header_mpir_h" "$ac_includes_default"
+if test "x$ac_cv_header_mpir_h" = xyes; then :
+
+    { $as_echo "$as_me:${as_lineno-$LINENO}: checking for __gmpz_init in -lmpir" >&5
+$as_echo_n "checking for __gmpz_init in -lmpir... " >&6; }
+if ${ac_cv_lib_mpir___gmpz_init+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lmpir  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char __gmpz_init ();
+int
+main ()
+{
+return __gmpz_init ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_mpir___gmpz_init=yes
+else
+  ac_cv_lib_mpir___gmpz_init=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_mpir___gmpz_init" >&5
+$as_echo "$ac_cv_lib_mpir___gmpz_init" >&6; }
+if test "x$ac_cv_lib_mpir___gmpz_init" = xyes; then :
+  have_mpz_init=yes
+fi
+
+fi
+
+
+  if test "$have_mpz_init" = "yes"; then
+    $as_echo "#define WITH_NUMBER_TYPES 1" >>confdefs.h
+
+    $as_echo "#define WITH_MPIR 1" >>confdefs.h
+
+    LIBS="-lmpir $LIBS" &&  if test "$verbose" = "yes"; then echo "    Prepending \"-lmpir\" to \$LIBS"; fi
+  else
+    { echo "Error:" "Required MPIR numeric support cannot be provided." >&2; exit 1; }
+  fi
 elif test "$with_bignum" = "mp"; then
   for library in "" "-lcrypto"; do
     ac_fn_c_check_header_mongrel "$LINENO" "mp.h" "ac_cv_header_mp_h" "$ac_includes_default"
@@ -21728,6 +21785,7 @@
 test "$with_dnet" = yes && echo "  Compiling in support for DNET."
 test "$with_modules" = "yes" && echo "  Compiling in support for dynamic shared object modules."
 test "$with_bignum" = "gmp" && echo "  Compiling in support for more number types using the GNU MP library."
+test "$with_bignum" = "mpir" && echo "  Compiling in support for more number types using the MPIR library."
 test "$with_bignum" = "mp" && echo "  Compiling in support for more number types using the BSD MP library."
 if test "$with_union_type" = yes ; then
   echo "  Using the union type for Lisp_Objects."