Use static_assert macro instead of Static_assert

Author: vrahane

include/tinycbor/compilersupport_p.h

@@ -53,9 +53,9 @@ extern "C" {
 #endif
 
 #if __STDC_VERSION__ >= 201112L || __cplusplus >= 201103L || __cpp_static_assert >= 200410
-#  define cbor_static_assert(x)         _Static_assert(x, #x)
+#  define cbor_static_assert(x)         static_assert(x, #x)
 #elif !defined(__cplusplus) && defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__ >= 406) && (__STDC_VERSION__ > 199901L)
-#  define cbor_static_assert(x)         _Static_assert(x, #x)
+#  define cbor_static_assert(x)         static_assert(x, #x)
 #else
 #  define cbor_static_assert(x)         ((void)sizeof(char[2*!!(x) - 1]))
 #endif