Hello,

This small patch allows solib-svr4.c to attempt to read 
linkmap info from core file when executable binary is not given.

e.g.:
$ gdb --core testsuite/gdb.base/bigcore.corefile
...
(gdb) info sharedlibrary
No shared libraries loaded at this time.
(gdb)

after patch:

$ ./gdb --nx --core  testsuite/gdb.base/bigcore.corefile
GNU gdb (GDB) 6.8.50.20090529-cvs
...
(gdb) info shared
 From        To          Syms Read   Shared Object Library
0x4cb3e470  0x4cb58844  No          /lib/libm.so.6
0x4ca18dd0  0x4cafe490  No          /lib/libc.so.6
0x4c9e5880  0x4c9fa8ef  No          /lib/ld-linux.so.2
(gdb)



Thanks,

-- 
Aleksandar Ristovski
QNX Software Systems


ChangeLog:


* solib-svr4.c (IGNORE_FIRST_LINK_MAP_ENTRY): Avoid 
dereferencing NULL
pointer.
(locate_base): If exec_bfd is NULL, use core_bfd if.