addressing #1647

[rsbivand]

I tried adding a template text pointing to https://rspatial.github.io/terra/. Running with PATH very restricted, I get:

$ PATH=/usr/bin:/usr/sbin ./configure
configure: CC: gcc
configure: CXX: g++ -std=gnu++17
checking for gdal-config... no
no
configure: error: gdal-config not found or not executable. 
*** Installing this package from source requires the prior
*** installation of external software, see for details
*** https://rspatial.github.io/terra/

[rhijmans]

Thank you very much! Could you also add this to to sf configure scripts -- so that these stay in sync? I copy the sf scripts if I see any changes there and only need to make a few minor changes.

[rsbivand]

@rhijmans I've created r-spatial/sf#2485, but the links differ in that sf's points to its information, terra's to its, which then points to sf's for more details.

[rhijmans]

excellent, thank you very much.