Add arm64 bti pads for range extension thunks.

Large arm64 binaries like chromium use range extension thunks
for accessing plt entries. Add bti landing pads for the
additional indirection.

upstream commit: 60827df765156cee6cca3dc5049388dde9dac1c0

ok kettenis@

merge lld-16.0.6

add .gnu.warning.SYMBOL support to ld.lld(1) to display the warnings in
these sections like ld.bfd(1)

e.g:
add.c(add.o:(add)): warning: sprintf() is often misused, please use snprintf()
add.c(add.o:(add)): warning: strcpy() is almost always misused, please use strlcpy()
add.c(add.o:(add)): warning: strcat() is almost always misused, please use strlcat()

ok deraadt@

Merge LLVM 13.0.0.

Merge LLVM 11.1.0.

branches: 1.1.1;
Initial revision

merge lld-16.0.6

add .gnu.warning.SYMBOL support to ld.lld(1) to display the warnings in
these sections like ld.bfd(1)

e.g:
add.c(add.o:(add)): warning: sprintf() is often misused, please use snprintf()
add.c(add.o:(add)): warning: strcpy() is almost always misused, please use strlcpy()
add.c(add.o:(add)): warning: strcat() is almost always misused, please use strlcat()

ok deraadt@

Merge LLVM 13.0.0.

Merge LLVM 11.1.0.

branches: 1.1.1;
Initial revision