Names that mask Fortran intrinsic functions cause errors.

When transpiling between Fortran and Python, declaring for example:

```
real, parameter :: tiny=1.e-32
```

and then referencing this name like in: 

```
if (x < tiny .and. x > 0.) then
```

will cause compiler errors e.g.:

```
   if (x < tiny() .and. x > 0.0) then
        1
Error: Expected a right parenthesis in expression at (1)
```