The component `_index` property is `long` but `_getcomp_index` returns `int`

[g5t]

As seen in the code generator, the property of each component representing its position along the instrument is long valued https://github.com/McStasMcXtrace/McCode/blob/c4c9421d630767f612703947bad4c82941220398/mcstas/src/cogen.c.in#L542

The _getcomp_index function finds the component which has a user-provided name and returns an int valued index. https://github.com/McStasMcXtrace/McCode/blob/c4c9421d630767f612703947bad4c82941220398/mcstas/src/cogen.c.in#L1032

This type difference is unlikely to produce problems, but may be problematic on systems where int and long are not type aliases for the same underlying integer value type.

To alleviate any possible comparison errors, the component _index and return value for _getcomp_index should have the same type -- either int or long.