trouble with libgomp/.deps directory building gcc 4.7.2

[Tim Bird <tim dot bird at am dot sony dot com>]

I am trying to build gcc-4.7.2 (September tarball release) on Ubuntu 12.04.
Some ways into the build I get the following error processing the libgomp directory:

make[3]: Entering directory `/a/home/tbird/work/auto-reduce/lto-work/obj-gcc/x86_64-unknown-linux-gnu/libgomp'
Makefile:456: .deps/affinity.Plo: No such file or directory
Makefile:457: .deps/alloc.Plo: No such file or directory
Makefile:458: .deps/bar.Plo: No such file or directory
Makefile:459: .deps/barrier.Plo: No such file or directory
Makefile:460: .deps/critical.Plo: No such file or directory
Makefile:461: .deps/env.Plo: No such file or directory
Makefile:462: .deps/error.Plo: No such file or directory
Makefile:463: .deps/fortran.Plo: No such file or directory
Makefile:464: .deps/iter.Plo: No such file or directory
Makefile:465: .deps/iter_ull.Plo: No such file or directory
Makefile:466: .deps/lock.Plo: No such file or directory
Makefile:467: .deps/loop.Plo: No such file or directory
Makefile:468: .deps/loop_ull.Plo: No such file or directory
Makefile:469: .deps/mutex.Plo: No such file or directory
Makefile:470: .deps/ordered.Plo: No such file or directory
Makefile:471: .deps/parallel.Plo: No such file or directory
Makefile:472: .deps/proc.Plo: No such file or directory
Makefile:473: .deps/ptrlock.Plo: No such file or directory
Makefile:474: .deps/sections.Plo: No such file or directory
Makefile:475: .deps/sem.Plo: No such file or directory
Makefile:476: .deps/single.Plo: No such file or directory
Makefile:477: .deps/task.Plo: No such file or directory
Makefile:478: .deps/team.Plo: No such file or directory
Makefile:479: .deps/time.Plo: No such file or directory
Makefile:480: .deps/work.Plo: No such file or directory
make[3]: *** No rule to make target `.deps/work.Plo'.  Stop.
make[3]: Leaving directory `/a/home/tbird/work/auto-reduce/lto-work/obj-gcc/x86_64-unknown-linux-gnu/libgomp'
make[2]: *** [all-stage1-target-libgomp] Error 2
make[2]: Leaving directory `/a/home/tbird/work/auto-reduce/lto-work/obj-gcc'
make[1]: *** [stage1-bubble] Error 2
make[1]: Leaving directory `/a/home/tbird/work/auto-reduce/lto-work/obj-gcc'
make: *** [all] Error 2

Has dependency-handling changed recently in this directory?
There is no .deps directory in libgomp.  Examining the
Makefile, it is not obvious how these files are supposed
to be generated.

My configure invocation was:
../gcc-4.7.2/configure --prefix=/opt/gcc-4.7 -enable-lto \
--with-plugin=ld=/usr/local/bin/ld-plugin --disable-nls \
--enable-languages=c,c++ --disable-libstdcxx-pch

Can anyone give me some tips for debugging this?

I had originally done a parallel build.  Based on some previous gcc
bug reports, I tried a 'make clean' and a serial build
('make' with no '-jx').
But I still get the same thing.

Any ideas would be appreciated.

Thanks,
 -- Tim

=============================
Tim Bird
Architecture Group Chair, CE Workgroup of the Linux Foundation
Senior Staff Engineer, Sony Network Entertainment
=============================