gawk: fix gensub usage

The third arg can either be a string with "g" or "G", or it is a number.
The empty string elicits a warning with newer versions like so:
gawk: scripts/sysd-rules.awk:56: warning: gensub: third argument `' treated as 1

ChangeLog

@@ -1,3 +1,8 @@
+2015-08-09  Mike Frysinger  <vapier@gentoo.org>
+
+	* nptl/tst-cancel-wrappers.sh: Change 3rd arg to gensub to 1.
+	* scripts/sysd-rules.awk: Likewise.
+
 2015-08-09  Mike Frysinger  <vapier@gentoo.org>
 
 	* iconvdata/tst-tables.sh: Change echo -n to printf.

nptl/tst-cancel-wrappers.sh

@@ -74,7 +74,7 @@ C["__xpg_sigpause"]=1
   seen=""
   seen_enable=""
   seen_disable=""
-  object=gensub(/^.*\[(.*)\]:$/,"\\1","",$0)
+  object=gensub(/^.*\[(.*)\]:$/, "\\1", 1, $0)
   next
 }
 {

scripts/sysd-rules.awk

@@ -53,7 +53,7 @@ BEGIN {
         if (target_pattern == "%") {
           command_suffix = "";
         } else {
-          prefix = gensub(/%/, "", "", target_pattern);
+          prefix = gensub(/%/, "", 1, target_pattern);
           command_suffix = " $(" prefix  "CPPFLAGS)";
         }
         target = "$(objpfx)" target_pattern o ":";