shtool mkln -s doesn't work like ln -s. Revert for now.

build/top.mk

@@ -118,7 +118,7 @@ DATE = date
 HOSTNAME = $(SHTOOL) echo -e "%h%d"
 LN = $(SHTOOL) mkln
 LN_H = $(SHTOOL) mkln -f
-LN_S = $(SHTOOL) mkln -f -s
+LN_S = @LN_S@
 MAKEINFO = @MAKEINFO@
 MKDIR = $(SHTOOL) mkdir -p
 MV = mv