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

*** 48,58 ****
  static const long double
          two24l = 16777216.0L,
          pio4   = 0.7853981633974483096156608458198757210495L;
  
  int
! __rem_pio2l(long double x, long double *y) {
          long double z, w;
          double t[5], v[5];
          int e0, i, nx, n, sign;
          const int *ipio2;
  
--- 48,59 ----
  static const long double
          two24l = 16777216.0L,
          pio4   = 0.7853981633974483096156608458198757210495L;
  
  int
! __rem_pio2l(long double x, long double *y)
! {
          long double z, w;
          double t[5], v[5];
          int e0, i, nx, n, sign;
          const int *ipio2;
  
*** 64,86 ****
                  return (0);
          }
          e0 = ilogbl(z) - 23;
          z = scalbnl(z, -e0);
          for (i = 0; i < 5; i++) {
!                 t[i] = (double) ((int) (z));
!                 z = (z - (long double) t[i]) * two24l;
          }
          nx = 5;
          while (t[nx - 1] == 0.0)
                  nx--;           /* skip zero term */
          ipio2 = _TBL_ipio2l_inf;
!         n = __rem_pio2m(t, v, e0, nx, 3, (const int *) ipio2);
!         z = (long double) v[2] + (long double) v[1];
!         w = (long double) v[0];
          y[0] = z + w;
          y[1] = z - (y[0] - w);
!         if (sign == 1) {
                  y[0] = -y[0];
                  y[1] = -y[1];
                  return (-n);
          }
          return (n);
--- 65,87 ----
                  return (0);
          }
          e0 = ilogbl(z) - 23;
          z = scalbnl(z, -e0);
          for (i = 0; i < 5; i++) {
!                 t[i] = (double)((int)(z));
!                 z = (z - (long double)t[i]) * two24l;
          }
          nx = 5;
          while (t[nx - 1] == 0.0)
                  nx--;           /* skip zero term */
          ipio2 = _TBL_ipio2l_inf;
!         n = __rem_pio2m(t, v, e0, nx, 3, (const int *)ipio2);
!         z = (long double)v[2] + (long double)v[1];
!         w = (long double)v[0];
          y[0] = z + w;
          y[1] = z - (y[0] - w);
!         if (sign != 0) {
                  y[0] = -y[0];
                  y[1] = -y[1];
                  return (-n);
          }
          return (n);