kcaching module variables

[remodietlicher]

Kcaching does not work if used on module variables and fails building with:
Variable x defined in the data clause has not been found

Original code

! Original code before transformation
use data, only: x
[...]
submodule dummy(a,b,c)
[...]
    DO i=1,10
        !$claw kcache data(x)
        y = x(i) * 10
        z = x(i) * y
    END DO
[...]
end submodule dummy

Expected code

! Expected code
use data, only: x
[...]
submodule dummy(a,b,c)
[...]
    DO i=1,10
        x_k = x(i)
        y = x_k * 10
        z = x_k * y
    END DO
[...]
end submodule dummy