patch 8.2.4549: cannot build with Motif and editres

Problem:    Cannot build with Motif and editres. (Tony Mechelynck)
Solution:   Fix configure mistake.
diff --git a/src/auto/configure b/src/auto/configure
index e603a46..a5497d8 100755
--- a/src/auto/configure
+++ b/src/auto/configure
@@ -10254,7 +10254,7 @@
 
 fi
 
-if -z "$SKIP_MOTIF"; then
+if test -z "$SKIP_MOTIF"; then
       if test -n "$GUI_INC_LOC"; then
     GUI_INC_LOC=-I"`echo $GUI_INC_LOC|sed 's%-I%%'`"
   fi