MFC r299114:
Do not leak THR_FLAGS_SUSPENDED from the previous suspend/resume
cycle.

PR: 209233

MFC r286582:
Pre-resolve symbols required for the deferred signal processing.

MFC r284385:
Fix typo in comment.

MFC r277488:
Do not allow pthread_sigmask() to block SIGCANCEL.

Fix known issues which blow up the process after dlopen("libthr.so")
(or loading a dso linked to libthr.so into process which was not
linked against threading library).

MFC r276630:
Remove interposing, fix malloc, reinstall signal handlers wrappers on
libthr load.

MFC r276681:
Avoid calling internal libc function through PLT or accessing data
though GOT.

MFC r277032:
Reduce the size of the interposing table and amount of
cancellation-handling code in the libthr.

MFC note:
r276646 ("do not erronously export 'openat' symbol from rtld") is not
applicable to stable/10 yet, since PATHFDS support was not merged.

MFC r258499:
Fix for the spurious signal handler call with zero signo in the threaded
process.

Approved by: re (hrs)

MFC r286582:
Pre-resolve symbols required for the deferred signal processing.

MFC r284385:
Fix typo in comment.

MFC r277488:
Do not allow pthread_sigmask() to block SIGCANCEL.

Fix known issues which blow up the process after dlopen("libthr.so")
(or loading a dso linked to libthr.so into process which was not
linked against threading library).

MFC r276630:
Remove interposing, fix malloc, reinstall signal handlers wrappers on
libthr load.

MFC r276681:
Avoid calling internal libc function through PLT or accessing data
though GOT.

MFC r277032:
Reduce the size of the interposing table and amount of
cancellation-handling code in the libthr.

MFC note:
r276646 ("do not erronously export 'openat' symbol from rtld") is not
applicable to stable/10 yet, since PATHFDS support was not merged.

MFC r258499:
Fix for the spurious signal handler call with zero signo in the threaded
process.

Approved by: re (hrs)