The amd64 build also hangs in nbctfmerge.  Here's a backtrace
and thread list:
(gdb) where
#0  0x00007f7ff689f63a in ___lwp_park60 () from /usr/lib/libc.so.12
#1  0x00007f7ff6c0b7e4 in ?? () from /usr/lib/libpthread.so.1
#2  0x00000000004048b1 in worker_thread ()
#3  0x00007f7ff6c0a9cc in ?? () from /usr/lib/libpthread.so.1
#4  0x00007f7ff6883d70 in ?? () from /usr/lib/libc.so.12
#5  0x0000000000000000 in ?? ()
(gdb) info threads
 Id   Target Id         Frame
 4    LWP 2             0x00007f7ff689f63a in ___lwp_park60 () from 
/usr/lib/libc.so.12
 3    LWP 3             0x00007f7ff7c0c50a in ___lwp_park60 () from 
/usr/libexec/ld.elf_so
 2    LWP 4             0x00007f7ff689f63a in ___lwp_park60 () from 
/usr/lib/libc.so.12
* 1    LWP 1             0x00007f7ff689f63a in ___lwp_park60 () from 
/usr/lib/libc.so.12
(gdb)
I'm disabling the amd64 builds, too.  Let's hope at least sparc still
builds so that we don't lose our entire automated testing
infrastructure to this.
--
Andreas Gustafsson, gson%gson.org@localhost
!DSPAM:56ba3df154578286514747!