Low: gdb security and bug fix update

[- 6.3.0.0-1.138]

• Fixed crash on cross-file resolving of opaque types (BZ 135488).

[- 6.3.0.0-1.137]

• Never lose any pending signal while attaching - resubmit them (BZ 189607).

[- 6.3.0.0-1.136]

• Bugfix segv on the source display by ^X 1 (BZ 202345).
• Support shared libraries >2GB on 64bit hosts - obstack update. (BZ 222814)

[- 6.3.0.0-1.135]

• Fix attach to a stopped process. (BZ 197584)

[- 6.3.0.0-1.134]

• Fix bug in patch for CVE-2006-4146. (BZ 203875)

[- 6.3.0.0-1.133]

• Avoid overflows and underflows in dwarf expression computation stack.