4.10 ld and NDS32

For NDS32, there are some options to select relaxation behavior. The linker relaxes objects according to these options.

`--m[no-]fp-as-gp'

Disable/enable fp-as-gp relaxation.

`--mexport-symbols=FILE'

Exporting symbols and their address into FILE as linker script.

`--m[no-]ex9'

Disable/enable link-time EX9 relaxation.

`--mexport-ex9=FILE'

Export the EX9 table after linking.

`--mimport-ex9=FILE'

Import the Ex9 table for EX9 relaxation.

`--mupdate-ex9'

Update the existing EX9 table.

`--mex9-limit=NUM'

Maximum number of entries in the ex9 table.

`--mex9-loop-aware'

Avoid generating the EX9 instruction inside the loop.

`--m[no-]ifc'

Disable/enable the link-time IFC optimization.

`--mifc-loop-aware'

Avoid generating the IFC instruction inside the loop.