RPostgres dependency

[MikkoVihtakari]

Does mfdb still need to depend on RPostgres or could it be moved to suggests? This dependency causes issues when trying to install mfdb on Windows.

[lentinj]

What's the windows upset? Compilation requiring the Postgres headers or somesuch? The CI always seems happy.

I don't think there's a technical reason, we by default connect to postgres unless told otherwise, but we can error with something explaining that Rpostgres needs to be installed if that's what is tried anyway. Our dependency doesn't run deeper than that.

I guess it could upset installs for @bthe, internally they'll be assuming install.packages('mfdb') also installs RPostgres, but it's not an arduous extra step. Any thoughts?

The same applies for RSqlite, although sqlite support is kinda pointless now and may be best to flat out remove it.

[kristinwindsland]

Microsoft Windows Enterprise Version 10.0.19042 Build 19042

[MikkoVihtakari]

Compilation requiring the Postgres headers or somesuch?

It complains about missing library libpq. Not sure how to install that on Windows...

[lentinj]

That's what I figured. I'd rather make the dependency a suggests than figure out how install libpq...

[lentinj]

Rpostgres is now optional on CRAN: 1218e2d / 4018124