ARC/NPTL: Fix __libc_sigaction redefinition with static links

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
ARC: ldso: Dont force frame pointer as it useless for unwinding on ARC

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
ARC: clone: Ensure that @fn returns back to clone

This showed up due to longstanding test/unistd/clone failure where post
clone, the callback was not exiting and rather falling thru in into main
program.

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