core-dump debugging does not work "No stack." -> remove of calls to inferior (especially cob_malloc) necessary

To leverage GDBs features I've tested debugging a core dump today. While it works in general (complete stack and all variables in "C" are visible), it does not work with cobcd.oy

The following is how I've did that:

1 create dump

$ mygdbwrapper MYPROG    # stops at breakpoint cob_runtime_error
(gdb) gcore /tmp/MYPROG.core.dump
Saved corefile /tmp/MYPROG.core.dump
(gdb) quit

2 load dump in a different terminal

$ CPRINT=1 gdb cobcrun /tmp/tst.core.dump --eval-command="set solib-search-path $COB_LIBRARY_PATH"
Reading symbols from cobcrun...
warning: Could not load shared library symbols for 101 libraries, e.g. ./MYPROG.so.
Use the "info sharedlibrary" command to see the complete listing.
Do you need "set solib-search-path" or "set sysroot"?
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib64/libthread_db.so.1".
Core was generated by '/opt/gnucobol/bin/cobcrun MPROG'.
Program terminated with signal SIGTRAP, Trace/breakpoint trap.
#0  cob_runtime_error (fmt=0x7ffff7bcbc76 "%s") at common.c:7191
7191            int     more_error_procedures = 1;
Reading symbols from /tmp/tst/MYPROG.so...
registering CPrint (Usage is "cprint" <COBOL identifier>") [Version 4.5]
registering CWatch (Usage is "cwatch <COBOL identifier>")
Reading symbols from /home/me/tst/PROG77.so...
Reading symbols from /tmp/tst/PROG47.so...
[99 more]
(gdb) bt
#0  cob_runtime_error (fmt=0x7ffff7bcbc76 "%s") at common.c:7191
#1  0x00007ffff7ba6f3c in cob_call_error () at call.c:1026
#2  0x00007ffff7ba7356 in cob_call_field (f=0x7fffe84e71f0 <VARIABLE_STRING_OBXXX_COB+176>, cs=0x0, errind=1, fold_case=0)
    at call.c:1164
#3  0x00007fffe813dfda in MYPROG_ (entry=0) at /tmp/tst/src/MYPROG.cob:188
#4  0x00007fffe81173a1 in MYPROG_ (entry=6596720) at /tmp/tst/src/MYPROG.cob:134
#5  0x0000000000401a00 in main (argc=2, argv=0x7fffffffc3b8) at cobcrun.c:421
(gdb) f 3
#3  0x00007fffe813dfda in MYPROG_ (entry=0) at tmp/tst/src/MYPROG.cob:188
271                MOVE "TST" TO VAR.
(gdb) cprint VAR
No stack.
(gdb) p cob_source_line
$1 = 188
(gdb) quit

SomedayTM we should also be able to debug coredumps. Other than the changes that may have been implemented to solve #28 (closed) we have to think about the question how to provide cbl-dbg with the variable data.

What definitely does not work is to query the running program - as there is none available.