Added "--pre-exit-hook"
Bugfixes of --pre-exit-hook
Added ability of runtime editing of "pre-exit-hook" value
Fixed the bug with infinite pre-exit-hook executing
Fixed potential free() of non-malloc()-ed string
Fixed -DCLUSTER_SUPPORT building bug

main.c: In function ‘ctx_check’:
main.c:1139:15: error: ‘utsname’ undeclared (first use in this function)
main.c:1139:15: note: each undeclared identifier is reported only once for each function it appears in
Fixed uninitialized exitcode
Added signal "SIGQUIT", "SIGTERM" made the same as "SIGINT"
Fixed a bug with incorrect "expanding" of %INCLUDE-LIST-PATH%
Added untested "socket_send_cb()"
Added a pointer to store user data to clsyncproc_t
Fixed -L in pkgconfig/libclsync.pc.in
Fixed potential segfault on socket_send_cb()
Fixed sentence with "--threading=full" in SUPPORT
Fixed a segfault in socket.c

0  0x00007f443f01a254 in _IO_vfprintf_internal (s=<optimized out>, format=<optimized out>, ap=<optimized out>) at vfprintf.c:1649
1  0x00007f443f01aebf in buffered_vfprintf (s=s@entry=0x7f443f376080 <_IO_2_1_stderr_>, format=format@entry=0x422498 "Got error while receiving a message from clsyncsock with sock %u: %s (errno: %u)",
    args=args@entry=0x7f443dd8cd80) at vfprintf.c:2318
2  0x00007f443f015cbe in _IO_vfprintf_internal (s=0x7f443f376080 <_IO_2_1_stderr_>, format=0x422498 "Got error while receiving a message from clsyncsock with sock %u: %s (errno: %u)", ap=0x7f443dd8cd80)
    at vfprintf.c:1301
3  0x0000000000404ffe in vprintf_stderr (fmt=0x422498 "Got error while receiving a message from clsyncsock with sock %u: %s (errno: %u)", args=0x7f443dd8cd80) at error.c:69
4  0x0000000000405795 in _error (function_name=0x422720 <__FUNCTION__.5185> "socket_procclsyncsock", fmt=0x422498 "Got error while receiving a message from clsyncsock with sock %u: %s (errno: %u)")
    at error.c:232
5  0x00000000004199ec in socket_procclsyncsock (arg=0x63b020 <sockthreaddata>) at socket.c:617
6  0x00007f443f382e0e in start_thread (arg=0x7f443dd8e700) at pthread_create.c:311
7  0x00007f443f0b793d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:113
the "state" was been moved to "ctx"
Fixed building
Fixed errno "returned" by socket_recv()
cmd_id format: %03u -> %u
Fixed "disconnect" handling