pkg-config version in x86-linux and x86_64-linux images taking a long time to resolve re2.pc

[mudge]

RE2 2024-06-01 uses more of Abseil which has caused the amount of time spent running pkg-config --libs-only-L --static re2.pc within the rake-compiler-dock images for x86-linux and x86_64-linux to significantly increase.

Both images use CentOS 7's latest version of pkgconfig: 0.27.1 but the latest version available is 0.29.2.

By manually downloading, compiling and installing the latest version of pkg-config on ghcr.io/rake-compiler/rake-compiler-dock-image:1.5.0-mri-x86-linux we can compare the difference:

# /usr/bin/pkg-config --version
0.27.1
# time /usr/bin/pkg-config --libs-only-L --static re2.pc
-L/Users/mudge/Projects/re2/ports/arm64-apple-darwin23/abseil/20240116.2/lib -L/Users/mudge/Projects/re2/ports/arm64-apple-darwin23/libre2/2024-06-01/lib  

real	3m41.007s
user	3m40.990s
sys	0m0.025s

# /usr/local/bin/pkg-config --version
0.29.2
# time /usr/local/bin/pkg-config --libs-only-L --static re2.pc
-L/Users/mudge/Projects/re2/ports/arm64-apple-darwin23/libre2/2024-06-01/lib -L/Users/mudge/Projects/re2/ports/arm64-apple-darwin23/abseil/20240116.2/lib

real	0m0.101s
user	0m0.083s
sys	0m0.018s

Is there a way for us to provide a newer version of pkg-config in the rake-compiler-dock images to work around this slowdown?

[mudge]

If you want to reproduce this:

1. Check out v2.12.0 of the re2 gem
2. Run bundle install
3. Run bundle exec rake compile
4. Start a Docker container with ports mounted, e.g. from within the re2 clone: docker run -v "$(PWD):/re2" --platform linux/amd64 -it ghcr.io/rake-compiler/rake-compiler-dock-image:1.5.0-mri-x86-linux /bin/bash
5. Set PKG_CONFIG_PATH inside the Docker container to include both Abseil and RE2, e.g. assuming you mounted the clone in /re2, export PKG_CONFIG_PATH=/re2/ports/arm64-apple-darwin23/abseil/20240116.2/lib/pkgconfig:/re2/ports/arm64-apple-darwin23/libre2/2024-06-01/lib/pkgconfig:$PKG_CONFIG_PATH
6. Run time pkg-config --libs-only-L --static /re2/ports/arm64-apple-darwin23/libre2/2024-06-01/lib/pkgconfig/re2.pc

[flavorjones]

Fascinatin, that's an incredible speedup for sure. I know that 0.28 and 0.29 addressed some recursive path issues, so I'll assume that's why it's faster.

Seems like we've got two options here ...

1. on the manylinux_2014 images, try to upgrade pkg-config to a modern version
2. drop manylinux_2014 in favor of a newer version which presumably will have a modern pkg-config

I was planning on doing (2) soon anyway, since the 2014 series is EOL as of 2024-06-30 (later this month!). See https://github.com/pypa/manylinux for details, and #122 for the issue describing this change in more detail.

Let me mess around with (1), though, since I could get that into a patch release on the 1.5.x branch, while (2) would really require a minor release.

[flavorjones]

Possible approach to (1) above is in #123

[flavorjones]

Closed in #123, will ship v1.5.1 promptly.