[gomp4] error on duplicate acc device_type entries

[Cesar Philippidis]

This patch teaches all of the front ends how to error on duplicate
device_type entries such as

  #pragma acc parallel  device_type (nvidia) num_gangs (1) \
     device_type (nvidia) num_gangs (20)

Before such clauses were silently ignored. I also fixed how invalid
device_type claues are reported in the fortran front end. It used report
"Invalid character" and now it states "Unclassifiable OpenACC directive".

I applied this patch to gomp-4_0-branch.

Cesar
-------------- next part --------------
A non-text attachment was scrubbed...
Name: dtype-dupes.diff
Type: text/x-patch
Size: 11683 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/gcc-patches/attachments/20150612/45ca4012/attachment.bin>