changed C11 keyword to _Alignas

so that it doesn't depend on #include

lib/common/compiler.h

@@ -305,7 +305,7 @@ MEM_STATIC int ZSTD_isPower2(size_t u) {
 # if defined(__GNUC__)
 #  define ZSTD_ALIGNED(a) __attribute__((aligned(a)))
 # elif defined(__STDC_VERSION__) && (__STDC_VERSION__ >= 201112L) /* C11 */
-#  define ZSTD_ALIGNED(a) alignas(a)
+#  define ZSTD_ALIGNED(a) _Alignas(a)
 #elif defined(_MSC_VER)
 #  define ZSTD_ALIGNED(n) __declspec(align(n))
 # else