opensc @0.16.0: integrate with p11-kit

[lbschenkel (Leonardo Brondani Schenkel)]

I'm attaching a patch that registers a opensc module in ${prefix}/share/p11-kit/modules so opensc will be automatically discovered by p11-kit.

I also introduced a new variant +p11kit (not enabled by default) that adds a runtime dependency to p11-kit and changes the module pkcs11-tool uses by default to the p11-kit module.

To the unfamiliar with p11-kit, it is a library with the purpose to enumerate and load all PKCS#11 modules in the system. Programs can link to p11-kit directly but p11-kit is also a PKCS#11 module itself, which allows it to be used by any program that supports loading such modules.

[lbschenkel (Leonardo Brondani Schenkel)]

Refreshed the patch to use p11-kit-proxy.so since it is now correctly built by the p11-kit port (#52486).

[dbevans (David B. Evans)]

Will test and commit assuming all is well. The only problem I see is that the /opt/local prefix is used rather than ${prefix} when setting p11_module_configs but I can fix that for you.

[lbschenkel (Leonardo Brondani Schenkel)]

I missed the stray /opt/local, sorry. I have updated the patch.

[dbevans (David B. Evans)]

Committed in r153518. Additional commit in r153519 to address a case-sensitivity issue (GitHub project name is OpenSC but tarball is opensc-0.16.tar.gz). Thanks for your enhancement.