Allow configure to detect whether ndbm.h or gdbm/ndbm.h is installed.
This allows dbmmodule.c to use either without having to add additional
options to the Modules/Setup file or make source changes.

(At least some Linux systems use gdbm to emulate ndbm, but only install
the ndbm.h header as /usr/include/gdbm/ndbm.h.)
diff --git a/config.h.in b/config.h.in
index 72f4fbc..8616811 100644
--- a/config.h.in
+++ b/config.h.in
@@ -272,9 +272,6 @@
 /* The number of bytes in a void *.  */
 #undef SIZEOF_VOID_P
 
-/* Define if you have the _getpty function.  */
-#undef HAVE__GETPTY
-
 /* Define if you have the alarm function.  */
 #undef HAVE_ALARM
 
@@ -362,6 +359,9 @@
 /* Define if you have the getpid function.  */
 #undef HAVE_GETPID
 
+/* Define if you have the _getpty function.  */
+#undef HAVE__GETPTY
+
 /* Define if you have the getpwent function.  */
 #undef HAVE_GETPWENT
 
@@ -521,12 +521,12 @@
 /* Define if you have the waitpid function.  */
 #undef HAVE_WAITPID
 
-/* Define if you have the <db.h> header file.  */
-#undef HAVE_DB_H
-
 /* Define if you have the <db_185.h> header file.  */
 #undef HAVE_DB_185_H
 
+/* Define if you have the <db.h> header file.  */
+#undef HAVE_DB_H
+
 /* Define if you have the <dirent.h> header file.  */
 #undef HAVE_DIRENT_H
 
@@ -536,6 +536,9 @@
 /* Define if you have the <fcntl.h> header file.  */
 #undef HAVE_FCNTL_H
 
+/* Define if you have the <gdbm/ndbm.h> header file.  */
+#undef HAVE_GDBM_NDBM_H
+
 /* Define if you have the <libutil.h> header file.  */
 #undef HAVE_LIBUTIL_H
 
@@ -548,6 +551,9 @@
 /* Define if you have the <ncurses.h> header file.  */
 #undef HAVE_NCURSES_H
 
+/* Define if you have the <ndbm.h> header file.  */
+#undef HAVE_NDBM_H
+
 /* Define if you have the <ndir.h> header file.  */
 #undef HAVE_NDIR_H
 
diff --git a/configure b/configure
index 3cb05bb..2038899 100755
--- a/configure
+++ b/configure
@@ -1,6 +1,6 @@
 #! /bin/sh
 
-# From configure.in Revision: 1.155 
+# From configure.in Revision: 1.156 
 
 # Guess values for system-dependent variables and create Makefiles.
 # Generated automatically using autoconf version 2.14.1 
@@ -1542,7 +1542,7 @@
 signal.h stdarg.h stddef.h stdlib.h thread.h unistd.h utime.h \
 sys/audioio.h sys/file.h sys/lock.h db_185.h db.h \
 sys/param.h sys/select.h sys/socket.h sys/time.h sys/times.h \
-sys/un.h sys/utsname.h sys/wait.h pty.h libutil.h
+sys/un.h sys/utsname.h sys/wait.h pty.h libutil.h ndbm.h gdbm/ndbm.h
 do
 ac_safe=`echo "$ac_hdr" | sed 'y%./+-%__p_%'`
 echo $ac_n "checking for $ac_hdr""... $ac_c" 1>&6
diff --git a/configure.in b/configure.in
index be8ee9b..af4056e 100644
--- a/configure.in
+++ b/configure.in
@@ -371,7 +371,7 @@
 signal.h stdarg.h stddef.h stdlib.h thread.h unistd.h utime.h \
 sys/audioio.h sys/file.h sys/lock.h db_185.h db.h \
 sys/param.h sys/select.h sys/socket.h sys/time.h sys/times.h \
-sys/un.h sys/utsname.h sys/wait.h pty.h libutil.h)
+sys/un.h sys/utsname.h sys/wait.h pty.h libutil.h ndbm.h gdbm/ndbm.h)
 AC_HEADER_DIRENT
 
 # checks for typedefs