Fix [http://core.tcl.tk/tcl/info/2f7cbd01c3|2f7cbd01c3]: tcl8.6.1 fails to build on FreeBSD 10.0
Fix [http://core.tcl.tk/tcl/info/2f7cbd01c3|2f7cbd01c3]: tcl8.6.1 fails to build on FreeBSD 10.0