fix warnings: unused variable 'XX' [-Wunused-variable]

src/qt/bitcoinstrings.cpp

@@ -1,6 +1,11 @@
 #include <QtGlobal>
 // Automatically generated by extract_strings.py
-static const char *bitcoin_strings[] = {QT_TRANSLATE_NOOP("bitcoin-core", ""
+#ifdef __GNUC__
+#define UNUSED __attribute__((unused))
+#else
+#define UNUSED
+#endif
+static const char UNUSED *bitcoin_strings[] = {QT_TRANSLATE_NOOP("bitcoin-core", ""
 "Unable to bind to port %d on this computer.  Bitcoin is probably already "
 "running."),
 QT_TRANSLATE_NOOP("bitcoin-core", "Warning: Disk space is low  "),