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.

1 files changed, 3 insertions, 4 deletions

diff --git a/lib/libc/sys/Symbol.map b/lib/libc/sys/Symbol.map
index 448bcce..f1f57ba 100644
--- a/lib/libc/sys/Symbol.map
+++ b/lib/libc/sys/Symbol.map
@@ -245,7 +245,6 @@ FBSD_1.0 {
 	setaudit;
 	setaudit_addr;
 	setauid;
-	setcontext;
 	setegid;
 	seteuid;
 	setgid;
@@ -286,7 +285,6 @@ FBSD_1.0 {
 	__stack_chk_guard;
 	stat;
 	statfs;
-	swapcontext;
 	swapoff;
 	swapon;
 	symlink;
@@ -351,7 +349,6 @@ FBSD_1.1 {
 	mkfifoat;
 	mknodat;
 	msgctl;
-	openat;
 	readlinkat;
 	renameat;
 	setfib;
@@ -1048,7 +1045,9 @@ FBSDprivate_1.0 {
 	__sys_write;
 	_writev;
 	__sys_writev;
-	__error_unthreaded;
+	__set_error_selector;
 	nlm_syscall;
 	gssd_syscall;
+	__libc_interposing_slot;
+	__libc_sigwait;
 };