Description of problem:
gcc build aborts when configuring libgomp:

checking for ppc64-redhat-linux-gcc... /builddir/build/BUILD/gcc-4.7.0-20120105/obj-ppc64-redhat-linux/./gcc/xgcc -B/builddir/build/BUILD/gcc-4.7.0-20120105/obj-ppc64-redhat-linux/./gcc/ -B/usr/ppc64-redhat-linux/bin/ -B/usr/ppc64-redhat-linux/lib/ -isystem /usr/ppc64-redhat-linux/include -isystem /usr/ppc64-redhat-linux/sys-include   
checking for C compiler default output file name... a.out
checking whether the C compiler works... configure: error: in `/builddir/build/BUILD/gcc-4.7.0-20120105/obj-ppc64-redhat-linux/ppc64-redhat-linux/libgomp':
configure: error: cannot run C compiled programs.

config.log has more info:

gcc version 4.7.0 20120106 (Red Hat 4.7.0-0.5) (GCC) 
configure:3646: $? = 0
configure:3635: /builddir/build/BUILD/gcc-4.7.0-20120106/obj-ppc64-redhat-linux/./gcc/xgcc -B/builddir/build/BUILD/gcc-4.7.0-20120106/obj-ppc64-redhat-linux/./gcc/ -B/usr/ppc64-redhat-linux/bin/ -B/usr/ppc64-redhat-linux/lib/ -isystem /usr/ppc64-redhat-linux/include -isystem /usr/ppc64-redhat-linux/sys-include    -V >&5
xgcc: error: unrecognized command line option '-V'
xgcc: fatal error: no input files
compilation terminated.
configure:3646: $? = 4
configure:3635: /builddir/build/BUILD/gcc-4.7.0-20120106/obj-ppc64-redhat-linux/./gcc/xgcc -B/builddir/build/BUILD/gcc-4.7.0-20120106/obj-ppc64-redhat-linux/./gcc/ -B/usr/ppc64-redhat-linux/bin/ -B/usr/ppc64-redhat-linux/lib/ -isystem /usr/ppc64-redhat-linux/include -isystem /usr/ppc64-redhat-linux/sys-include    -qversion >&5
xgcc: error: unrecognized command line option '-qversion'
xgcc: fatal error: no input files
compilation terminated.
configure:3646: $? = 4
configure:3666: checking for C compiler default output file name
configure:3688: /builddir/build/BUILD/gcc-4.7.0-20120106/obj-ppc64-redhat-linux/./gcc/xgcc -B/builddir/build/BUILD/gcc-4.7.0-20120106/obj-ppc64-redhat-linux/./gcc/ -B/usr/ppc64-redhat-linux/bin/ -B/usr/ppc64-redhat-linux/lib/ -isystem /usr/ppc64-redhat-linux/include -isystem /usr/ppc64-redhat-linux/sys-include    -O2 -g -Wall -fexceptions -fstack-protector --param=ssp-buffer-size=4 -mminimal-toc   conftest.c  >&5
configure:3692: $? = 0
configure:3729: result: a.out
configure:3745: checking whether the C compiler works
configure:3754: ./a.out
/builddir/build/BUILD/gcc-4.7.0-20120106/libgomp/configure: line 3756: 30853 Segmentation fault      (core dumped) ./$ac_file
configure:3758: $? = 139
configure:3765: error: in `/builddir/build/BUILD/gcc-4.7.0-20120106/obj-ppc64-redhat-linux/ppc64-redhat-linux/libgomp':
configure:3769: error: cannot run C compiled programs.


gdb shows this:
#0  0x00000000100004c0 in .frame_dummy ()
(gdb) bt
#0  0x00000000100004c0 in .frame_dummy ()
#1  0x000000001000059c in .__libc_csu_init ()
#2  0x0000000010000550 in .__libc_csu_init ()
#3  0x00000fff891f2238 in generic_start_main (main=@0x10010a08: 0x100005b8 <.__libc_csu_fini>, argc=<optimized out>, 
    ubp_av=0xffff3e19a68, auxvec=0xffff3e19fb0, init=@0x10010a18: 0x100005c8 <.__do_global_ctors_aux>, 
    rtld_fini=<optimized out>, stack_end=Unhandled dwarf expression opcode 0xfa
) at ../csu/libc-start.c:185
#4  0x00000fff891f24a4 in __libc_start_main (argc=<optimized out>, ubp_av=<optimized out>, ubp_ev=<optimized out>, 
    auxvec=<optimized out>, rtld_fini=<optimized out>, stinfo=<optimized out>, stack_on_entry=<optimized out>)
    at ../sysdeps/unix/sysv/linux/powerpc/libc-start.c:92
#5  0x0000000000000000 in ?? ()


Version-Release number of selected component (if applicable):
gcc-4.7.0-0.4.fc17

How reproducible:
always

Steps to Reproduce:
1. ppc-koji build --scratch f17 gcc-4.7.0-0.4.fc17.src.rpm
2.
3.
  
Actual results:
http://ppc.koji.fedoraproject.org/koji/taskinfo?taskID=356037


Additional info:
I can give you access to PPC64 LPAR on my Power7 machine with a F17 mock chroot where this is reproducable, just ping me on IRC (karsten / Kick_)
I've marked this as urgent as this is blocking the F17 mass rebuild on PPC.