I'm building a cross toolchain for ultrasparc, and when I build the final gcc (with a proper glibc 2.11.1 built), I get:

checking for C compiler default output file name... configure: error: in `/tmp/nix-build-fg665ygndf0l90symznxdarn7cpffbhz-gcc-4.4.3-sparc64-unknown-linux-stage-final.drv-0/build/sparc64-unknown-linux/libgomp':
configure: error: C compiler cannot create executables

Config.log shows:
  $ /tmp/nix-build-fg665ygndf0l90symznxdarn7cpffbhz-gcc-4.4.3-sparc64-unknown-linux-stage-final.drv-0/gcc-4.4.3/libgomp/configure --cache-file=./config.cache --with-cross-host=x86_64-unknown-linux-gnu --prefix=/nix/store/hvbynr246lx5ajxd2akvs4ry3ns90py3-gcc-4.4.3-sparc64-unknown-linux-stage-final --disable-multilib --with-ppl=/nix/store/mb40dibxpvnx57xbddnzdvy2hxnnipp9-ppl-0.10.2 --with-cloog=/nix/store/4ffjd1j014rn91bckprbyz2zl7r7fc6i-cloog-ppl-0.15.7 --with-gmp=/nix/store/00fbkpgn2g1xrp39crrvnyjb2kj3m6js-gmp-4.3.2 --with-mpfr=/nix/store/dzqizzqfaalqdxv1a0sy9zv2w2w8f5nq-mpfr-2.4.2 --disable-libstdcxx-pch --without-included-gettext --with-system-zlib --with-cpu=ultrasparc --with-headers=/nix/store/gvr35zv0b7155fwxx4gd6yqcmkrkx2rn-glibc-2.11.1-sparc64-unknown-linux/include --enable-__cxa_atexit --enable-long-long --enable-threads=posix --enable-nls --enable-languages=c,c++ --program-transform-name=s,^,sparc64-unknown-linux-, --with-target-subdir=sparc64-unknown-linux --build=x86_64-unknown-linux-gnu --host=sparc64-unknown-linux --target=sparc64-unknown-linux --srcdir=../../../gcc-4.4.3/libgomp

....

configure:2569: checking for C compiler default output file name
configure:2572: /tmp/nix-build-fg665ygndf0l90symznxdarn7cpffbhz-gcc-4.4.3-sparc64-unknown-linux-stage-final.drv-0/build/./gcc/xgcc -B/tmp/nix-build-fg665ygndf0l90symznxdarn7cpffbhz-gcc-4.4.3-sparc64-unknown-linux-stage-final.drv-0/build/./gcc/ -g0 -O2 -B/nix/store/gvr35zv0b7155fwxx4gd6yqcmkrkx2rn-glibc-2.11.1-sparc64-unknown-linux/lib -idirafter /nix/store/gvr35zv0b7155fwxx4gd6yqcmkrkx2rn-glibc-2.11.1-sparc64-unknown-linux/include -Wl,-L/nix/store/gvr35zv0b7155fwxx4gd6yqcmkrkx2rn-glibc-2.11.1-sparc64-unknown-linux/lib -g0 -O2 -B/nix/store/gvr35zv0b7155fwxx4gd6yqcmkrkx2rn-glibc-2.11.1-sparc64-unknown-linux/lib -idirafter /nix/store/gvr35zv0b7155fwxx4gd6yqcmkrkx2rn-glibc-2.11.1-sparc64-unknown-linux/include -Wl,-L/nix/store/gvr35zv0b7155fwxx4gd6yqcmkrkx2rn-glibc-2.11.1-sparc64-unknown-linux/lib    -g0 -O2 -B/nix/store/gvr35zv0b7155fwxx4gd6yqcmkrkx2rn-glibc-2.11.1-sparc64-unknown-linux/lib -idirafter /nix/store/gvr35zv0b7155fwxx4gd6yqcmkrkx2rn-glibc-2.11.1-sparc64-unknown-linux/include -Wl,-L/nix/store/gvr35zv0b7155fwxx4gd6yqcmkrkx2rn-glibc-2.11.1-sparc64-unknown-linux/lib conftest.c  >&5
/tmp/nix-build-fg665ygndf0l90symznxdarn7cpffbhz-gcc-4.4.3-sparc64-unknown-linux-stage-final.drv-0/build/./gcc/cc1: error while loading shared libraries: /tmp/nix-build-fg665ygndf0l90symznxdarn7cpffbhz-gcc-4.4.3-sparc64-unknown-linux-stage-final.drv-0/build/./gcc/libgcc_s.so.1: ELF file data encoding not little-endian
configure:2575: $? = 1