[RFC] Fortran search path for intrinsic includes and modules

[FX Coudert]

> The first thing I'd like to be merged (if possible) immediately
> after 4.1 branches is the libgfortran thread safety patch.
> It is independent from the rest of gomp (gomp just depends on that)

This patch actually fixes a few bugs in bugzilla (don't have the numbers 
now, but many bugs with -fdefault-integer-8 for example). Would it be 
possible to get it into 4.1 as well, so that we don't struggle too much 
on those? Just after the branching, it shouldn't be much work.

FX