[Bug bootstrap/47736] New: [4.6 Regression] libquadmath build broken with pre-2.10 glibc

["jsm28 at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47736

           Summary: [4.6 Regression] libquadmath build broken with
                    pre-2.10 glibc
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: bootstrap
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jsm28@gcc.gnu.org
                CC: jakub@gcc.gnu.org


Bootstrap on x86_64-unknown-linux-gnu with glibc 2.7 (Ubuntu 8.04 LTS) fails
with:

/scratch/joseph/fsf/gcc-mainline/libquadmath/printf/quadmath-printf.c: In
function 'quadmath_snprintf':
/scratch/joseph/fsf/gcc-mainline/libquadmath/printf/quadmath-printf.c:220:7:
error: 'struct printf_info' has no member named 'user'
/scratch/joseph/fsf/gcc-mainline/libquadmath/printf/quadmath-printf.c: In
function 'flt128_ais':
/scratch/joseph/fsf/gcc-mainline/libquadmath/printf/quadmath-printf.c:288:11:
error: 'const struct printf_info' has no member named 'user'
/scratch/joseph/fsf/gcc-mainline/libquadmath/printf/quadmath-printf.c: In
function 'flt128_printf_fp':
/scratch/joseph/fsf/gcc-mainline/libquadmath/printf/quadmath-printf.c:367:12:
error: 'const struct printf_info' has no member named 'user'
/scratch/joseph/fsf/gcc-mainline/libquadmath/printf/quadmath-printf.c: In
function 'flt128_printf_fphex':
/scratch/joseph/fsf/gcc-mainline/libquadmath/printf/quadmath-printf.c:380:12:
error: 'const struct printf_info' has no member named 'user'

It appears that this member was new in glibc 2.10, and so configure checks or
version checks are needed to avoid requiring it when building with older glibc.