Fix for https://bugs.gentoo.org/show_bug.cgi?id=486664

--- a/configure
+++ b/configure
@@ -65,10 +65,10 @@
 do
 	for TCLVER_TRY in "8.6" "8.5" "8.4" "8.3" "8.2" "8.1" "8.0"
 	do
-		if [ -z $TCLSH ]
+		if [ -z "$TCLSH" ]
 		then
 			TCLSH_TRY=${TCLPATH_TRY}tclsh${TCLVER_TRY}
-			if [ -f $TCLSH_TRY ]
+			if [ -f "$TCLSH_TRY" ]
 			then
 				TCLSH=$TCLSH_TRY
 				echo "===> Found Tclsh in: $TCLSH"
@@ -76,7 +76,7 @@
 		fi
 	done
 done
-if [ -f $TCLSH ]
+if [ -f "$TCLSH" ]
 then
 	TCL_VER=`echo puts \\$tcl_version | $TCLSH -`
 	USE_TCL='-DUSE_TCL'