Update the patching to work on Windows without admin.

[clalancette]

Signed-off-by: Chris Lalancette clalancette@openrobotics.org

Like we've done elsewhere, update google_benchmark_vendor to use git apply for applying patches. This allows it to work on Windows without administrator.

@cottsay Note that I did not change this to use git to fetch the sources as we did in uncrustify_vendor. It seemed to work without problems for me on all of Linux, Windows, and macOS without that. Nevertheless, I'd appreciate your insight here into whether I should change this to use GIT_REPOSITORY instead.

[cottsay]

It seemed to work without problems for me on all of Linux, Windows, and macOS without that.

It only appears to be working because the patches aren't build-ciritical. The insidious nature of the problem that switching to a git upstream works around is that it is a completely silent failure - the only reason we noticed to begin with was that the patches that failed to apply caused a build break.

To repro, set --verbose on your git-apply operations, run git init . in your ROS workspace, and build the package again. You should see this:

$ git init .
Initialized empty Git repository in /opt/ros_src/rolling/.git/
$ colcon build --symlink --merge --install-base /opt/ros/rolling --cmake-args -DFORCE_BUILD_VENDOR_PKG=ON --packages-select google_benchmark_vendor --event-handler console_start_end- --cmake-clean-first --cmake-force-configure
--- stderr: google_benchmark_vendor                              
Skipped patch 'cmake/thread_safety_attributes.cpp'.
Skipped patch 'CMakeLists.txt'.
---

Summary: 1 package finished [2.18s]
  1 package had stderr output: google_benchmark_vendor

[clalancette]

Thanks for the info. I'll give this a try a little later on (and switch to using GIT as appropriate).

[clalancette]

All right, well, I couldn't reproduce the problem locally. But given that we went through the same thing in uncrustify, I'm going to assume that we need to switch over to GIT to make this work properly. So I did that in e76349f.