Update on shared memory coarrays

[Nicolas König]

Hello world,

here is an update for the coarray_native branch.

TL;DR: New stuff and bugfixes, need help with testsuite integration.

Toon's test case has provided the opportunity to fix numerous
bugs; it now runs correctly.  It can be found at
http://moene.org/~toon/random-weather .

Here's a list of the major changes since the last email:

* According to popular demand, the library has been renamed
   cas_shared, and any references to "native coarrays" have been expunged
   (except for the branch name, which we cannot change). the directory under
   libgfortran has been moved to cas_shared and the prefix in the front 
end and
   library has been changed to cas (for coarray_shared).  The option is also
   called -fcoarray=shared now.

* Use of pthread_barrier_t and associated functions has been removed, so 
there
   is a chance that the library compiles on MacOS now.

* STAT and ERRMSG have been implemented.

So, generally, the branch seems to be in a usable state now. Major
missing features at the moment are:

* allocatable components in coarrays
* teams
* gcc testsuite integration and testcases

Since I'd like to get the branch merged as quickly as possible, any
help with the testsuite would be greatly appreciated.

So, if you could give it a spin (especially to test if there are
platforms where it does not bootstrap), that would be great.

   Nicolas