Tcl 8.6 by default disallows the use of interp->result - TIP #330, http://www.tcl.tk/cgi-bin/tct/tip/330.html . oasys 1.3.0 uses interp->result in several places and so does not build with Tcl 8.6. The attached patch fixes this via the use of Tcl_GetStringResult as advised by upstream.
patch for oasys 1.3.0 to build with tcl 8.6