I think the subversion build failure with gcc4 is due to an optimiser bug.

The code in question is subversion/tests/libsvn_wc/translate-test.c,
around line 637:

    if (dst_eol)  /* verify the promised consistent eol style */
       {
         if (strncmp (contents->data + idx, dst_eol, strlen (dst_eol))
!= 0)

and it's segfaulting in the coredump on the strncmp line, with dst_eol
== NULL which Just Isn't Cricket.

jorton@jedi:libsvn_wc$ gdb ./translate-test
GNU gdb Red Hat Linux (6.1post-1.20040607.61rh)
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and
you are
welcome to change it and/or distribute copies of it under certain
conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for
details.
This GDB was configured as "i386-redhat-linux-gnu"...Using host
libthread_db library "/lib/tls/libthread_db.so.1".
(gdb) run
Starting program:
/local/dist/subversion/devel/subversion-1.1.3/subversion/tests/libsvn_wc/translate-test
[Thread debugging using libthread_db enabled]
[New Thread -1208121664 (LWP 3139)]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread -1208121664 (LWP 3139)]
0x0804956d in substitute_and_verify (test_name=Variable "test_name" is
not available.
) at subversion/tests/libsvn_wc/translate-test.c:637
637               if (strncmp (contents->data + idx, dst_eol, strlen
(dst_eol)) != 0)
(gdb) print dst_eol
$1 = 0x0
(gdb) l
632
633           idx += strlen (expect[i]);
634
635           if (dst_eol != NULL)  /* verify the promised consistent
eol style */
636             {
637               if (strncmp (contents->data + idx, dst_eol, strlen
(dst_eol)) != 0)
638
639                 return svn_error_createf
640                   (SVN_ERR_IO_CORRUPT_EOL, NULL,
641                    "'%s' has wrong eol style at line %"
APR_SIZE_T_FMT, dst_fname,
(gdb)

Changing the code to be:
      if (dst_eol) 
        {
          printf("%s\n", dst_eol);

          if (strncmp (contents->data + idx, dst_eol, strlen
(dst_eol)) != 0)

and it works fine.

Likewise building translate-test.c at -O0 and it works fine.