This is the last item of the OpenACC 3.3 spec. It includes the
implicit-name version of 'routine', plus significant refactorings to
make the two work together. The implicit name version is represented as
an attribute on the function call. This patch also implements the
clauses for the implicit-name version, as well as the A.3.4 warning.
The 'routine' construct has two forms, one which takes the name of a
function that it applies to, and another where it implicitly figures it
out based on the next declaration. This patch implements the former with
the required restrictions on the name and the function-static-variables
as specified.
What has not been implemented is any clauses for this, any of the A.3.4
warnings, or the other form.
The 'declare' construct is the first of two 'declaration' level
constructs, so it is legal in any place a declaration is, including as a
statement, which this accomplishes by wrapping it in a DeclStmt. All
clauses on this have a 'same scope' requirement, which this enforces as
declaration context instead, which makes it possible to implement these
as a template.
The 'link' and 'device_resident' clauses are also added, which have some
similar/small restrictions, but are otherwise pretty rote.
This patch implements all of the above.
