Add --enable-ros3-vfd build flag

[djhoese]

The whole point of #122 was to play with the new read-only S3 VFD functionality of HDF5 1.12. Apparently I forgot to check if it actually got enabled by default (it doesn't). This PR enables the feature and as far as I know does not have any additional requirements or effect any other features of the library since it should be a libcurl-based contact to a remote S3 storage. More info here:

https://portal.hdfgroup.org/display/HDF5/Configuration+and+Setup+for+HDF5+Read+Only+S3+VFD

Checklist

• Used a personal fork of the feedstock to propose changes
• Bumped the build number (if the version is unchanged)
• Reset the build number to 0 (if the version changed)
• Re-rendered with the latest conda-smithy (Use the phrase @conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• Ensured the license file is being packaged.

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

[scopatz]

last element shouldn't have a trailing slash

[djhoese]

I thought it was odd but the static one had it too. Any idea why that works?

Edit: I mean master had it that way so I copied it.

[scopatz]

Probably because there are just blank lines following it

[djhoese]

checking if the Read-Only S3 virtual file driver (VFD) is enabled... no
configure: error: The Read-Only S3 VFD was requested but cannot be built.
                      Please check that openssl and cURL are available on your
                      system, and/or re-configure without option
                      --enable-ros3-vfd.

Looks like SSL and curl are needed. For some reason I assumed they would have already been added to the conda-forge build. I'm guessing that makes this a bigger deal to include (people maybe not wanting ssl and curl installed)?

[scopatz]

I mean, I don't think it is that big of a deal to add ssl and curl deps

[djhoese]

At a loss again. Configure seems to find the headers for curl just fine:

2020-08-06T20:56:17.8136018Z checking curl/curl.h usability... yes
2020-08-06T20:56:17.8485835Z checking curl/curl.h presence... yes
2020-08-06T20:56:17.8490187Z checking for curl/curl.h... yes

But then later during compilation:

2020-08-06T21:05:52.0771711Z Making install in src
2020-08-06T21:05:52.4242117Z make[1]: Entering directory '/home/conda/feedstock_root/build_artifacts/hdf5_split_1596747167656/work/src'
2020-08-06T21:05:52.4243388Z   CC       H5FDros3.lo
2020-08-06T21:05:52.9916273Z In file included from H5FDros3.c:35:0:
2020-08-06T21:05:52.9917163Z H5FDs3comms.h:60:10: fatal error: curl/curl.h: No such file or directory
2020-08-06T21:05:52.9917621Z  #include <curl/curl.h>
2020-08-06T21:05:52.9917909Z           ^~~~~~~~~~~~~
2020-08-06T21:05:52.9918201Z compilation terminated.

[scopatz]

Maybe you need to pass the location of curl into the configure script? Sometimes that is needed

[djhoese]

I'm 90% the configure script is the thing that is giving the first output of "checking" and successfully finding curl.h. Otherwise would I do --with-curl="${PREFIX}/include/curl?

[djhoese]

@isuruf I suppose we should just remove the verbosity stuff and then this is good for review?

[isuruf]

Why remove verbose stuff? It's good for debugging when something fails.

[djhoese]

Ah ok. I just thought you were adding it to help figure out why curl wasn't showing up. Nevermind then. Ready for review.

[isuruf]

I just thought you were adding it to help figure out why curl wasn't showing up.

I was. It'll still be useful for future when something goes wrong.

[scopatz]

Great work @djhoese and thanks @isuruf!