target/10806: Illegal instruction calling function in shared object on AIX

[Stuart F. Downing]

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=10806

I have simplified the test case further.
Replace mod.c with the following

static char static_thing = 0;

void fun ()
{
}

The symptom goes away if 

* the initializer is removed
* the base type of static_thing is changed to int (but NOT if changed
  to short)
* the declaration for static_thing is moved after fun

Seems like an alignment problem, but I wasn't able to find any
switches controlling alignment or initializers to make the symptom go
away.
-- 
Stuart Downing