fix wrong value of FLT_EVAL_METHOD for x86_64

arch/x86_64/bits/float.h

@@ -1,5 +1,5 @@
 #define FLT_ROUNDS 1
-#define FLT_EVAL_METHOD 1
+#define FLT_EVAL_METHOD 0
 
 #define LDBL_MIN     3.3621031431120935063e-4932L
 #define LDBL_MAX     1.1897314953572317650e+4932L