fix typing issue

Author: rmalmain

linux-user/strace.c

@@ -54,7 +54,7 @@ struct flags {
 };
 
 /* No 'struct flags' element should have a zero mask. */
-#define FLAG_BASIC(V, M, N)      { V, M | QEMU_BUILD_BUG_ON_ZERO(!(M)), N }
+#define FLAG_BASIC(V, M, N)      { V, M | QEMU_BUILD_BUG_ON_ZERO(!((M) > 0 ? 1 : 0)), N }
 
 /* common flags for all architectures */
 #define FLAG_GENERIC_MASK(V, M)  FLAG_BASIC(V, M, #V)