Add gstack script

This commit adds support for a `gstack' command which Fedora has
been carrying for many years. gstack is a natural counterpart to
the gcore command. Whereas gcore dumps a core file, gstack prints
stack traces of a running process.

There are many improvements over Fedora's version of this script.
The dependency on procfs is gone; gstack will run anywhere gdb
runs. The only runtime dependencies are bash and awk.

The script includes suggestions from gdb/32325 to include
versioning and help. [If this approach to gdb/32325 is acceptable,
I could propagate the solution to gcore/gdb-add-index.]

I've rewritten the documentation, integrating it into the User Manual.
The manpage is now output using this one source.

Example run (on x86_64 Fedora 40)

$ gstack --help
Usage: gstack [-h|--help] [-v|--version] PID
Print a stack trace of a running program

  -h, --help         Print this message then exit.
  -v, --version      Print version information then exit.
$ gstack -v
GNU gstack (GDB) 16.0.50.20241119-git
$ gstack 12345678
Process 12345678 not found.
$ gstack $(pidof emacs)
Thread 6 (Thread 0x7fd5ec1c06c0 (LWP 2491423) "pool-spawner"):
#0  0x00007fd6015ca3dd in syscall () at /lib64/libc.so.6
#1  0x00007fd60b31eccd in g_cond_wait () at /lib64/libglib-2.0.so.0
#2  0x00007fd60b28a61b in g_async_queue_pop_intern_unlocked () at /lib64/libglib-2.0.so.0
#3  0x00007fd60b2f1a03 in g_thread_pool_spawn_thread () at /lib64/libglib-2.0.so.0
#4  0x00007fd60b2f0813 in g_thread_proxy () at /lib64/libglib-2.0.so.0
#5  0x00007fd6015486d7 in start_thread () at /lib64/libc.so.6
#6  0x00007fd6015cc60c in clone3 () at /lib64/libc.so.6
#7  0x0000000000000000 in ??? ()

Thread 5 (Thread 0x7fd5eb9bf6c0 (LWP 2491424) "gmain"):
#0  0x00007fd6015be87d in poll () at /lib64/libc.so.6
#1  0x0000000000000001 in ??? ()
#2  0xffffffff00000001 in ??? ()
#3  0x0000000000000001 in ??? ()
#4  0x000000002104cfd0 in ??? ()
#5  0x00007fd5eb9be320 in ??? ()
#6  0x00007fd60b321c34 in g_main_context_iterate_unlocked.isra () at /lib64/libglib-2.0.so.0

Thread 4 (Thread 0x7fd5eb1be6c0 (LWP 2491425) "gdbus"):
#0  0x00007fd6015be87d in poll () at /lib64/libc.so.6
#1  0x0000000020f9b558 in ??? ()
#2  0xffffffff00000003 in ??? ()
#3  0x0000000000000003 in ??? ()
#4  0x00007fd5d8000b90 in ??? ()
#5  0x00007fd5eb1bd320 in ??? ()
#6  0x00007fd60b321c34 in g_main_context_iterate_unlocked.isra () at /lib64/libglib-2.0.so.0

Thread 3 (Thread 0x7fd5ea9bd6c0 (LWP 2491426) "emacs"):
#0  0x00007fd6015ca3dd in syscall () at /lib64/libc.so.6
#1  0x00007fd60b31eccd in g_cond_wait () at /lib64/libglib-2.0.so.0
#2  0x00007fd60b28a61b in g_async_queue_pop_intern_unlocked () at /lib64/libglib-2.0.so.0
#3  0x00007fd60b28a67c in g_async_queue_pop () at /lib64/libglib-2.0.so.0
#4  0x00007fd603f4d0d9 in fc_thread_func () at /lib64/libpangoft2-1.0.so.0
#5  0x00007fd60b2f0813 in g_thread_proxy () at /lib64/libglib-2.0.so.0
#6  0x00007fd6015486d7 in start_thread () at /lib64/libc.so.6
#7  0x00007fd6015cc60c in clone3 () at /lib64/libc.so.6
#8  0x0000000000000000 in ??? ()

Thread 2 (Thread 0x7fd5e9e6d6c0 (LWP 2491427) "dconf worker"):
#0  0x00007fd6015be87d in poll () at /lib64/libc.so.6
#1  0x0000000000000001 in ??? ()
#2  0xffffffff00000001 in ??? ()
#3  0x0000000000000001 in ??? ()
#4  0x00007fd5cc000b90 in ??? ()
#5  0x00007fd5e9e6c320 in ??? ()
#6  0x00007fd60b321c34 in g_main_context_iterate_unlocked.isra () at /lib64/libglib-2.0.so.0

Thread 1 (Thread 0x7fd5fcc45280 (LWP 2491417) "emacs"):
#0  0x00007fd6015c9197 in pselect () at /lib64/libc.so.6
#1  0x0000000000000000 in ??? ()

Since this is essentially a complete rewrite of the original
script and documentation, I've chosen to only keep a 2024 copyright date.

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Tom Tromey <tom@tromey.com>

0 files changed, 0 insertions, 0 deletions