[Bug bootstrap/60830] [4.9 Regression] ICE on bootstrapping on cygwin

["bernd.edlinger at hotmail dot de" <gcc-bugzilla@gcc.gnu.org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60830

--- Comment #29 from Bernd Edlinger <bernd.edlinger at hotmail dot de> ---
Hmm, that is really strange.

the crash happens in __gcc_deregister_frame.
just break at this function and step.
The first call is GetModuleHandle (LIBGCC_SONAME) which
returns NULL, so the weak default __deregister_frame_info
is used. BUT the address is wrong by 0x10.

00401170 <___gcc_deregister_frame>:
  401170:       55                      push   %ebp
  401171:       89 e5                   mov    %esp,%ebp
  401173:       83 ec 18                sub    $0x18,%esp
  401176:       c7 04 24 20 71 47 00    movl   $0x477120,(%esp)
  40117d:       ff 15 50 b4 4c 00       call   *0x4cb450
  401183:       83 ec 04                sub    $0x4,%esp
  401186:       85 c0                   test   %eax,%eax
  401188:       ba 10 25 47 00          mov    $0x472510,%edx
  40118d:       74 16                   je     4011a5
<___gcc_deregister_frame+0x35>
  40118f:       c7 44 24 04 67 71 47    movl   $0x477167,0x4(%esp)
  401196:       00
  401197:       89 04 24                mov    %eax,(%esp)
  40119a:       ff 15 54 b4 4c 00       call   *0x4cb454
  4011a0:       83 ec 08                sub    $0x8,%esp
  4011a3:       89 c2                   mov    %eax,%edx
  4011a5:       85 d2                   test   %edx,%edx
  4011a7:       74 09                   je     4011b2
<___gcc_deregister_frame+0x42>
  4011a9:       c7 04 24 38 b0 4b 00    movl   $0x4bb038,(%esp)
  4011b0:       ff d2                   call   *%edx

=> this call goes to 0x472510 instead of 0x472520.
....

  4724ff:       e8 fc 01 00 00          call   472700 <_free>
  472504:       8b 44 24 1c             mov    0x1c(%esp),%eax
  472508:       83 c4 28                add    $0x28,%esp
  47250b:       5b                      pop    %ebx
  47250c:       c3                      ret
  47250d:       89 d0                   mov    %edx,%eax
  47250f:       ba e4 ac 4c 00          mov    $0x4cace4,%edx
  472514:       eb a6                   jmp    4724bc
<___deregister_frame_info_bases+0x6c>
  472516:       8d 76 00                lea    0x0(%esi),%esi
  472519:       8d bc 27 00 00 00 00    lea    0x0(%edi,%eiz,1),%edi

00472520 <___deregister_frame_info>:
  472520:       e9 2b ff ff ff          jmp    472450
<___deregister_frame_info_bases>
  472525:       8d 74 26 00             lea    0x0(%esi,%eiz,1),%esi
  472529:       8d bc 27 00 00 00 00    lea    0x0(%edi,%eiz,1),%edi