Fix all warnings and enable -Werror for gptfdisk.

Bug: 26936282
Change-Id: Id7e9ec5e769e1abedc1d2e36bff2c5488b1c4b3e
diff --git a/gptcl.cc b/gptcl.cc
index 7c1d5cf..bdb4693 100644
--- a/gptcl.cc
+++ b/gptcl.cc
@@ -109,7 +109,7 @@
       {"version", 'V', POPT_ARG_NONE, NULL, 'V', "display version information", ""},
       {"zap", 'z', POPT_ARG_NONE, NULL, 'z', "zap (destroy) GPT (but not MBR) data structures", ""},
       {"zap-all", 'Z', POPT_ARG_NONE, NULL, 'Z', "zap (destroy) GPT and MBR data structures", ""},
-      POPT_AUTOHELP { NULL, 0, 0, NULL, 0 }
+      POPT_AUTOHELP { NULL, 0, 0, NULL, 0, NULL, NULL }
    };
 
    // Create popt context...