protobuf: improve discovery of protoc executable in build context

[SpaceIm]

While building googleapis shared against protobuf shared, and protobuf static in build requirements, I've realized that the protoc flavor linked to shared protobuf was used, instead of the static flavor.

So this PR fixes this issue, by ensuring that even for native build, protoc from build requirements is used when available, instead of protoc from requirements.

---

• I've read the contributing guidelines.
• I've used a recent Conan client version close to the currently deployed.
• I've tried at least one configuration locally with the conan-center hook activated.

[github-actions]

🤖 Beep Boop! This pull request is making changes to 'recipes/protobuf//'.

👋 @Hopobcn you might be interested. 😉

[ghost]

I detected other pull requests that are modifying protobuf/all recipe:

• protobuf: add v4.25.3, v5.26.0 #21622
• protobuf: bump patch versions #21592
• Adding protobuf/3.5.1 #20627
• Fixed issue #18927 #18929
• protobuf: add version 4.23.1 #16098

This message is automatically generated by https://github.com/ericLemanissier/conan-center-conflicting-prs so don't hesitate to report issues/improvements there.

[SpaceIm]

ERROR: Missing binary: protobuf/3.20.0:eb5173dacad2e669146d68b06c433f666807fac6

protobuf/3.20.0: WARN: Can't find a 'protobuf/3.20.0' package binary 'eb5173dacad2e669146d68b06c433f666807fac6' for the configuration:
[settings]
arch=x86_64
build_type=Release
compiler=msvc
compiler.cppstd=14
compiler.runtime=dynamic
compiler.runtime_type=Release
compiler.version=192
os=Windows
[options]
debug_suffix=True
lite=False
shared=False
with_rtti=True
with_zlib=True
[requires]
zlib/1.3.Z

ERROR: Missing prebuilt package for 'protobuf/3.20.0'
Check the available packages using 'conan list protobuf/3.20.0:* -r=remote'
'conan test' tested packages must exist, and '--build' argument is used only for the 'test_package' dependencies, not for the tested dependencies

More Info at 'https://docs.conan.io/2/knowledge/faq.html#error-missing-prebuilt-package'

@RubenRBS @danimtb @uilianries Is c3i logic broken? There should be a "lock" delaying execution of test package for shared=True flavor of each settings, until shared=False package of the same settings is available (and if shared=True is the default option value in recipe, it should be the opposite), otherwise when tested recipe is in build requirements of test package, we end up with these missing binaries.

For example here c3i complains that eb5173dacad2e669146d68b06c433f666807fac6 package is missing, it's the static flavor of msvc 192 static Release and it has been built (and even tested) successfully as you can see in https://c3i.jfrog.io/c3i/misc-v2/summary.html?json=https://c3i.jfrog.io/c3i/misc-v2/logs/pr/20089/5-windows-msvc/protobuf/3.20.0//summary.json, so why test package of msvc 192 shared Release can't find this package?

A solution for v2 pipeline might be to inject shared value in requirements AND build requirements.. BUT, it may lead to many issues on macOS due to SIP.

[SpaceIm]

I guess that it should pass if I trigger c3i again, since package is available now...

[SpaceIm]

Well, it's super tedious. I've opened #20534

[SpaceIm]

It's a bug of v2 pipeline: #19501 (comment)

[conan-center-bot]

Conan v1 pipeline ✔️

All green in build 19 (97d1c08d6f632ccee7ab5ffa20b5110a04bb2610):

• protobuf/3.21.9:
  All packages built successfully! (All logs)

• protobuf/3.19.6:
  All packages built successfully! (All logs)

• protobuf/3.21.12:
  All packages built successfully! (All logs)

• protobuf/3.17.1:
  All packages built successfully! (All logs)

• protobuf/3.20.0:
  All packages built successfully! (All logs)

• protobuf/3.20.3:
  All packages built successfully! (All logs)

• protobuf/3.18.3:
  All packages built successfully! (All logs)

---

Conan v2 pipeline ✔️

Note: Conan v2 builds are now mandatory. Please read our discussion about it.

All green in build 19 (97d1c08d6f632ccee7ab5ffa20b5110a04bb2610):

• protobuf/3.21.12:
  All packages built successfully! (All logs)

• protobuf/3.21.9:
  All packages built successfully! (All logs)

• protobuf/3.21.4:
  All packages built successfully! (All logs)

• protobuf/3.19.6:
  All packages built successfully! (All logs)

• protobuf/3.19.4:
  All packages built successfully! (All logs)

• protobuf/3.20.0:
  All packages built successfully! (All logs)

• protobuf/3.18.1:
  All packages built successfully! (All logs)

• protobuf/3.17.1:
  All packages built successfully! (All logs)

[pgeler]

is there a way to roll back this? as this causing more harm than good #21737