Define qfldbl and ldbl_to_q only for x87 code.

These two functions assume x87 80-bit representation.

src/qfloat.c

@@ -383,6 +383,7 @@ double dbl_flip_lsb(double d)
 	return u64_to_f64(c);
 }
 
+#ifdef X87_ASM
 /* qfloat --> long double conversion utility.
 Example: x = QLN2:
 	hi = 0x3fe62e42fefa39ef,
@@ -430,6 +431,7 @@ struct qfloat ldbl_to_q(long double x)
 	q.lo = (x87_mant<<53);
 	return q;
 }
+#endif
 
 
 /* Convert IEEE64 double to qfloat. */

src/qfloat.h

@@ -130,10 +130,10 @@ uint64 qfdbl_as_uint64(const struct qfloat q);
 double qfdbl		(const struct qfloat q);
 double qfdbl_wrong_way_rnd(struct qfloat q);
 double dbl_flip_lsb	(double d);
-long double qfldbl	(const struct qfloat q);
+long double qfldbl	(const struct qfloat q);	// This should only be used for x87 code.
 // double / long-double --> qfloat conversions:
 struct qfloat dbl_to_q	(double d);
-struct qfloat ldbl_to_q	(long double ld);
+struct qfloat ldbl_to_q	(long double ld);		// This should only be used for x87 code.
 // int --> qfloat conversion:
 struct qfloat i64_to_q	(int64 i64);
 struct qfloat i128_to_q	(uint128 i);