Update the protobuf recipe

[coatless]

This should update the existing protobuf as a library for CRAN builds.

We're assuming the CRAN build system has autoconf, automake, and libtool available.

/ cc @eddelbuettel

[coatless]

@s-u Anyway we could get this merged and built on CRAN? @eddelbuettel would like to release a new version of RProtobuf that supports macOS.

[eddelbuettel]

Actually I don't -- I'd simply prefer for the existing package to build.

Several of my packages never built on that esteemed OS, and @s-u did take to kindly to my suggestion of allowing me to disable builds there.

But I, as a maintainer, now get punished by CRAN for ERROR (as packages progress more slowly). Yet ERROR is all I can get on macOS as soon as happen to deploy a non-standard library.

It really is not ideal. @coatless is kindly offering to build some libraries but we are running into "issues".

[coatless]

@s-u Any chance this could get merged? Soon (TM)?

[s-u]

Thanks, committed, tested, deployed.

However, there is a bug in RProtoBuf which prevents it from building anyway -- it uses the wrong compiler in configure. It has to pick up CXX and CC from R (which is clang), but the configure defaults to GCC for tests instead which won't work here so it fails. To be precise, you need probably something like

: ${CC=`${R_HOME}/bin/R CMD config CC`}
: ${CXX=`${R_HOME}/bin/R CMD config CXX`}

in configure before running any tests.

[eddelbuettel]

However, there is a bug in RProtoBuf which prevents it from building anyway

Will fix. Same idiom is used in other places, and Kurt usually reminds me to do it everywhere. Surprised it slipped here for so long.

[s-u]

Thanks. That may have been the issue before, since we did have protobuf 2.6.1 which should have been compatible.
Also I can set an override of CC/CXX for RProtoBuf in the meantime if it helps - I don't know when you get to push the new version.

[eddelbuettel]

Within days, possibly tomorrow.

But please do it anyway. Better to disentangle dependencies on any critical path.

[eddelbuettel]

@s-u Can you, by chance, try the version in the GH repo ?

That change was made in July, a good two weeks after the most recent release:
https://github.com/eddelbuettel/rprotobuf/blob/a181677d3cabb66d3fd536f480ac8ac68ba7b981/configure.ac#L15-L21

[eddelbuettel]

@s-u: Is there something you can do about this one, please?
https://www.r-project.org/nosvn/R.check/r-oldrel-osx-x86_64/RProtoBuf-00check.html