Remove uses of sprintf in gen-posix-conf-vars.awk

Simply some code by replacing sprintf in the awk script.

ChangeLog

@@ -1,3 +1,7 @@
+2015-01-02  Siddhesh Poyarekar  <siddhesh@redhat.com>
+
+	* scripts/gen-posix-conf-vars.awk (END): Don't use sprintf.
+
 2014-12-31  Joseph Myers  <joseph@codesourcery.com>
 
 	[BZ #17748]

scripts/gen-posix-conf-vars.awk

@@ -68,11 +68,8 @@ END {
 
     # Build a name -> sysconf number associative array to print a C array at
     # the end.
-    if (prefix_conf[c] == "SPEC") {
-      name = sprintf ("%s", c)
-      num = sprintf ("%s_%s", sc_prefixes[c], conf[c])
-      spec[name] = num
-    }
+    if (prefix_conf[c] == "SPEC")
+      spec[c] = sc_prefixes[c] "_" conf[c]
   }
 
   # Print the specification array.  Define the macro NEED_SPEC_ARRAY before