11175 libm should use signbit() correctly
11188 c99 math macros should return strictly backward compatible values

*** 65,75 ****
          small = 1.0e-10,
          big = 1.0e10;
  /* INDENT ON */
  
  double
! tanh(double x) {
          double t, y, z;
          int signx;
          volatile double dummy __unused;
  
          if (isnan(x))
--- 65,76 ----
          small = 1.0e-10,
          big = 1.0e10;
  /* INDENT ON */
  
  double
! tanh(double x)
! {
          double t, y, z;
          int signx;
          volatile double dummy __unused;
  
          if (isnan(x))
*** 92,100 ****
                          return (x);
                  }
          } else if (!finite(t))
                  return (copysign(1.0, x));
          else
!                 return (signx == 1 ? -z + small * small : z - small * small);
  
!         return (signx == 1 ? -z : z);
  }
--- 93,101 ----
                          return (x);
                  }
          } else if (!finite(t))
                  return (copysign(1.0, x));
          else
!                 return ((signx != 0) ? -z + small * small : z - small * small);
  
!         return ((signx != 0) ? -z : z);
  }