ARC: buildsys: switch libc to kbuild-style

Tracks 1b3025b7352

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
ARC: Enable no-legacy-syscalls ABI (v3)

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
ARC: setjmp.h split

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
ARC: use defconfgs

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
ARC: ucontext typedef missing

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
ARC: fix vfork wrapper using clone syscall

clone syscall handler in kernel expects child stack pointer to be
correctly setup.

The vfork libc wrapper (clone syscall based) was failing to do this
(partly because the earlier vfork syscall based wrapper didn't have to).

This showed up as random Busybox:init crashes - when dispatching
/etc/inittab entires (where vfork is used).

While at it - also zeroed out the other 3 args expected by kernel
handler.

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Workaround a R_ARC_NONE relo generated in dyn-linked executables

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
libpthread.old: allow to build for no-legacy-syscalls ABI

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
vfork: Fix flags when using clone syscall

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
utimes: Export utimensat based utimes

sys/time.h has libc_hidden_proto(utimes) which generates the hidden
"__GI_utimes" symbol reference, and common/utimes.c has a
libc_hidden_def(utimes) which generates the exported "utimes" alias.

As part of no-legacy-syscall kernel ABI, Commit 80dc2ed05
"utimes: Use utimensat if arch does not have the utimes syscall"
introduced a new wrapper, but missed the corresponding libc_hidden_def,
causing Busybox (1.20.0) link to fail (for ARC).

---------------->8-------------------
....
touch.c:(.text.touch_main+0xdc): undefined reference to `utimes'
touch.c:(.text.touch_main+0x114): undefined reference to `utimes'
libbb/lib.a(copy_file.o): In function `copy_file':
copy_file.c:(.text.copy_file+0x446): undefined reference to `utimes'
collect2: ld returned 1 exit status
---------------->8-------------------

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>