[fortran] Add runtime warning mechanism to libgfortran

[FX Coudert]

>>        * trans.c (gfc_trans_code): Remove main_program and attr.
>>        (gfc_generate_code): Move them here.
> 
>  this ChangeLog entry is incorrect.  I merely moved
> those two variables into the if block.

You're right. What about:

	* trans.c (gfc_generate_code): Move main_program and attr.

FX