Merge pull request #3443 from YosysHQ/micko/resetall_undefineall

resetall does not affect text defines, but undefineall does

frontends/verilog/preproc.cc

@@ -961,6 +961,11 @@ frontend_verilog_preproc(std::istream                 &f,
 		}
 
 		if (tok == "`resetall") {
+			default_nettype_wire = true;
+			continue;
+		}
+
+		if (tok == "`undefineall" && sv_mode) {
 			defines.clear();
 			global_defines_cache.clear();
 			continue;