--- /dev/null
+dnl
+dnl Copyright 2005 Free Software Foundation, Inc.
+dnl
+dnl This file is part of GNU Radio
+dnl
+dnl GNU Radio is free software; you can redistribute it and/or modify
+dnl it under the terms of the GNU General Public License as published by
+dnl the Free Software Foundation; either version 3, or (at your option)
+dnl any later version.
+dnl
+dnl GNU Radio is distributed in the hope that it will be useful,
+dnl but WITHOUT ANY WARRANTY; without even the implied warranty of
+dnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+dnl GNU General Public License for more details.
+dnl
+dnl You should have received a copy of the GNU General Public License
+dnl along with GNU Radio; see the file COPYING. If not, write to
+dnl the Free Software Foundation, Inc., 51 Franklin Street,
+dnl Boston, MA 02110-1301, USA.
+dnl
+
+# GR_NO_UNDEFINED()
+#
+# Detemine whether we need to use the -no-undefined linker flag
+# when building shared libraries.
+# Sets NO_UNDEFINED to "" or "-no-undefined"
+#
+# As far as I can tell, we need -no-undefined only when building
+# windows DLLs. This occurs when using MinGW and Cygwin.
+#
+# For now, we stub this out.
+
+AC_DEFUN([GR_NO_UNDEFINED],[
+ AC_REQUIRE([AC_CANONICAL_HOST])
+ no_undefined=""
+ case "${host_os}" in
+ *mingw* | *cygwin*)
+
+ # on MinGW/Cygwin extra LDFLAGS are required
+ no_undefined="-no-undefined"
+ ;;
+ esac
+ AC_SUBST(NO_UNDEFINED,[$no_undefined])
+])