MINOR: threads: Add THREAD_LOCAL macro
When compiled with threads support, this marco is set to __thread. Else it is
empty.
diff --git a/include/common/config.h b/include/common/config.h
index f5d290f..f06ba3b 100644
--- a/include/common/config.h
+++ b/include/common/config.h
@@ -41,6 +41,12 @@
# define CONFIG_HAP_MEM_OPTIM
#endif /* CONFIG_HAP_NO_MEM_OPTIM */
+#ifdef USE_THREAD
+#define THREAD_LOCAL __thread
+#else
+#define THREAD_LOCAL
+#endif
+
/* CONFIG_HAP_INLINE_FD_SET
* This makes use of inline FD_* macros instead of calling equivalent
* functions. Benchmarks on a Pentium-M show that using functions is