[Fortran, OpenACC] Reject vars of different scope in $acc declare (PR94120)

[Fortran, OpenACC] Reject vars of different scope in $acc declare (PR94120)

2020-03-12  Tobias Burnus  <tobias@codesourcery.com>

        PR middle-end/94120
        * openmp.c (gfc_match_oacc_declare): Accept function-result
        variables; reject variables declared in a different scoping unit.

2020-03-12  Tobias Burnus  <tobias@codesourcery.com>

        PR middle-end/94120
        * gfortran.dg/goacc/pr78260-2.f90: Correct scan-tree-dump-times.
        Extend test case to result variables.
        * gfortran.dg/goacc/declare-2.f95: Actually check module-declaration
        restriction of OpenACC.
        * gfortran.dg/goacc/declare-3.f95: Remove case where this
        restriction is violated.
        * gfortran.dg/goacc/pr94120-1.f90: New.
        * gfortran.dg/goacc/pr94120-2.f90: New.
        * gfortran.dg/goacc/pr94120-3.f90: New.