Fix a brunch of -Wextra warnings:

- 'static' is not at beginning of declaration;
  - unused parameter;
  - comparison between signed and unsigned.

examples/nfc-list.c

@@ -33,6 +33,7 @@
   #endif
 #endif
 
+#include <err.h>
 #include <stdio.h>
 #include <stddef.h>
 #include <stdlib.h>
@@ -54,6 +55,10 @@ int main(int argc, const char* argv[])
   nfc_target_info_t nti;
   nfc_device_desc_t *pnddDevices;
 
+  if (argc > 1) {
+    errx (1, "usage: %s", argv[0]);
+  }
+
   // Display libnfc version
   const char* acLibnfcVersion = nfc_version();
   printf("%s use libnfc %s\n", argv[0], acLibnfcVersion);