Fix some warnings on Windows

ethsock.c

@@ -384,7 +384,7 @@ static bool intf_get_info(const char *intf, uint8_t *hwaddr, DWORD *index)
 {
 	PIP_ADAPTER_INFO adapters, adapter;
 	DWORD ret;
-	ULONG i, bufLen = 0;
+	ULONG bufLen = 0;
 	bool found = false;
 
 	if ((ret = GetAdaptersInfo(NULL, &bufLen)) != ERROR_BUFFER_OVERFLOW) {

main.c

@@ -80,7 +80,7 @@ void usage(FILE *fp)
 #ifdef NMRPFLASH_WINDOWS
 void require_admin()
 {
-	SID_IDENTIFIER_AUTHORITY auth = SECURITY_NT_AUTHORITY;
+	SID_IDENTIFIER_AUTHORITY auth = { SECURITY_NT_AUTHORITY };
 	PSID group = NULL;
 	BOOL admin, success = AllocateAndInitializeSid(
 		&auth, 2, SECURITY_BUILTIN_DOMAIN_RID, DOMAIN_ALIAS_RID_ADMINS,

nmrpd.h

@@ -56,6 +56,7 @@
 #include <iphlpapi.h>
 #include <ws2tcpip.h>
 #include <windows.h>
+#include <conio.h>
 #endif
 
 #ifndef MIN