local-patches: sync with xtensa gcc call0 ABI support

[jcmvbkbc]

Fixed:

• possible a7/a15 corruption in functions with 6+ argument words and frame pointer enabled;
• vararg functions;
• setjmp/longjmp;
• nested functions;
• profiling with -pg option (_mcount call);

A bit improved code generation for SP manipulations.

Known broken:

• __builtin_return_address;
• __builtin_frame_address for frames other than current.

Unknown:

• C++ exception handling.

Signed-off-by: Max Filippov [email protected]