Handling of -fpic in ASM_OUTPUT_MI_THUNK in sparc

[Teemu Torma]

It seems that ASM_OUTPUT_MI_THUNK in sparc emits normal funcion call
sequence when the file compiled is compiled with -fpic.  This sounds
very slow, since the call goes thru the dynamic table and can lead to
an additional register window trap.

Is there any reason why not to emit the thunk to a writable segment?
In that case -fpic condition could be taken away.

Besides, the current test does not help if the main program compiled
without -fpic emits thunks that call methods in a shared library.

Teemu