google-benchmark: new package

[glebm]

Description

Adds a package for https://github.com/google/benchmark

Type(s)

• bugfix
• enhancement
• security fix

Tested on

Component versions: DevToolsCore-798.0; DevToolsSupport-794.0

Verification

Have you

• followed our Commit Message Guidelines?
• squashed and minimized your commits?
• checked that there aren't other open pull requests for the same change?
• referenced existing tickets on Trac with full URL in commit message?
• checked your Portfile with port lint?
• tried existing tests with sudo port test?
• tried a full install with sudo port -vst install?
• tested basic functionality of all binary files?
• checked that the Portfile's most important variants haven't been broken?

/cc @AJenbo

[kencu]

Generally speaking, macports as a policy always wants the shared library version installed if there is a choice. That way all the consumers of the library don't have to be rebuilt for every small change in the library, only for big ABI-changing updates.

If there is some reason why the static lib version is a better choice, and there may be, that is OK, but usually needs a bit of explanation.

[glebm]

Got you. I had simply cargo-culted this from gtest. Now changed to build a shared library by default along with a static variant.

[glebm]

On Tiger, linking to the resulting library fails in the same way as gtest (https://trac.macports.org/ticket/71511)