lfs6.6编译第一遍gcc的时候报错，求助下。

zhouyi65

In file included from exceptions.c:23:
mpfr-impl.h:160:3: error: #error "BITS_PER_MP_LIMB must be a power of 2, and >= 32"
mpfr-impl.h:174:3: error: #error "Can't compute log2(BITS_PER_MP_LIMB)"
exceptions.c: In function 'mpfr_set_emin':
exceptions.c:43: error: 'BITS_PER_MP_LIMB' undeclared (first use in this function)
exceptions.c:43: error: (Each undeclared identifier is reported only once
exceptions.c:43: error: for each function it appears in.)
exceptions.c: In function 'mpfr_get_emin_min':
exceptions.c:57: error: 'BITS_PER_MP_LIMB' undeclared (first use in this function)
exceptions.c: In function 'mpfr_get_emin_max':
exceptions.c:63: error: 'BITS_PER_MP_LIMB' undeclared (first use in this function)
exceptions.c: In function 'mpfr_set_emax':
exceptions.c:79: error: 'BITS_PER_MP_LIMB' undeclared (first use in this function)
exceptions.c: In function 'mpfr_get_emax_min':
exceptions.c:93: error: 'BITS_PER_MP_LIMB' undeclared (first use in this function)
exceptions.c: In function 'mpfr_get_emax_max':
exceptions.c:98: error: 'BITS_PER_MP_LIMB' undeclared (first use in this function)
make[3]: *** [exceptions.lo] Error 1
make[3]: Leaving directory `/opt/lfs/sourcess/gcc-build/mpfr'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/opt/lfs/sourcess/gcc-build/mpfr'
make[1]: *** [all-mpfr] Error 2
make[1]: Leaving directory `/opt/lfs/sourcess/gcc-build'
make: *** [all] Error 2