+AC_ARG_ENABLE(backend,AC_HELP_STRING([--enable-backend=<backend>],[Choose the backend database to use. Defaults to db4.]), [], [enable_backend="db4"])
+
+AC_MSG_CHECKING([which key database backend to use])
+AC_MSG_RESULT([$enable_backend])
+AC_CHECK_FILE([$srcdir/keydb_$enable_backend.c], ,AC_MSG_ERROR([non existent key database backend $enable_backend]))
+
+if test "x$enable_backend" = "xdb4"
+then
+ AC_CHECK_HEADER(db.h, have_db_h="yes", have_db_h="no")
+ AC_MSG_CHECKING(for libdb version in db.h)
+ printf "#include <db.h>\nDB_VERSION_MAJOR DB_VERSION_MINOR\n" >conftest.c
+ set `eval $ac_cpp conftest.c | egrep '^ *[[0-9]] *'`; v="$1"; vv="$2"
+ AC_MSG_RESULT($v.$vv)
+ if test "$v" -ne 4; then
+ AC_MSG_ERROR([ * onak requires libdb version 4])
+ fi
+ for db in "db-$v.$vv" "db$v.$vv" "db-$v" "db$v" "db"; do
+ AC_MSG_CHECKING(for db_create in lib$db)
+ oldLIBS="$LIBS"
+ LIBS="$LIBS -l$db"
+ AC_TRY_LINK([#include <db.h>], db_create(0, 0, 0),
+ have_libdb="yes", have_libdb="no")
+ AC_MSG_RESULT($have_libdb)
+ if test "$have_libdb" != "no"; then break; fi
+ LIBS="$oldLIBS"
+ done
+ if test "$have_libdb" = "no" -o "$have_db_h" = "no"; then
+ AC_MSG_ERROR(libdb not found.)
+ fi
+ AC_DEFINE(HAVE_LIBDB, 1, [libdb found])
+else if test "x$enable_backend" = "xpg"
+then
+ AC_CHECK_LIB(pq, PQsetdbLogin,,
+ AC_MSG_ERROR([cannot compile PostgreSQL backend without libpq]))
+fi
+fi
+
+AC_SUBST(DBTYPE, $enable_backend)
+