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);

examples/nfc-mfclassic.c

@@ -47,7 +47,7 @@ static mifare_tag mtKeys;
 static mifare_tag mtDump;
 static bool bUseKeyA;
 static bool bUseKeyFile;
-static uint32_t uiBlocks;
+static uint8_t uiBlocks;
 static byte_t keys[] = {
   0xff,0xff,0xff,0xff,0xff,0xff,
   0xd3,0xf7,0xd3,0xf7,0xd3,0xf7,

examples/nfcip-initiator.c

@@ -26,6 +26,7 @@
   #include "config.h"
 #endif // HAVE_CONFIG_H
 
+#include <err.h>
 #include <stdio.h>
 #include <string.h>
 #include <nfc/nfc.h>
@@ -40,6 +41,10 @@ int main(int argc, const char *argv[])
   size_t szRecvBits;
   byte_t send[] = "Hello World!";
 
+  if (argc > 1) {
+    errx (1, "usage: %s", argv[0]);
+  }
+
   pnd = nfc_connect(NULL);
   if (!pnd || !nfc_initiator_init(pnd)
       || !nfc_initiator_select_dep_target(pnd, NM_PASSIVE_DEP, NULL, 0,

examples/nfcip-target.c

@@ -27,6 +27,7 @@
   #include "config.h"
 #endif // HAVE_CONFIG_H
 
+#include <err.h>
 #include <stdio.h>
 #include <nfc/nfc.h>
 
@@ -39,6 +40,10 @@ int main(int argc, const char *argv[])
   byte_t send[] = "Hello Mars!";
   nfc_device_t *pnd = nfc_connect(NULL);
 
+  if (argc > 1) {
+    errx (1, "usage: %s", argv[0]);
+  }
+
   if (!pnd || !nfc_target_init(pnd, abtRecv, &szRecvBits)) {
     printf("unable to connect or initialize\n");
     return 1;