spdlog: make sure libdirs is empty when header_only=True

[gegles]

Specify library name and version: spdlog/1.12.0

This PR removes the following warning (on macOS) when the library is used in header_only=True mode:

ld: warning: directory not found for option '-L/Users/gegles/.conan2/p/b/spdlo6818b9a6a2366/p/lib'

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• 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.

[ericLemanissierBot]

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

• spdlog: update fmt/10.1.0 #19192

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

[conan-center-bot]

Conan v1 pipeline ✔️

All green in build 2 (b5d61a81c8374ab8733d20247e12deee512ce162):

• spdlog/1.10.0:
  All packages built successfully! (All logs)

• spdlog/1.11.0:
  All packages built successfully! (All logs)

• spdlog/1.9.2:
  All packages built successfully! (All logs)

• spdlog/1.9.1:
  All packages built successfully! (All logs)

• spdlog/1.8.5:
  All packages built successfully! (All logs)

• spdlog/1.12.0:
  All packages built successfully! (All logs)

---

Conan v2 pipeline ✔️

Note: Conan v2 builds may be required once they are on the v2 ready list

All green in build 2 (b5d61a81c8374ab8733d20247e12deee512ce162):

• spdlog/1.12.0:
  All packages built successfully! (All logs)

• spdlog/1.11.0:
  All packages built successfully! (All logs)

• spdlog/1.10.0:
  All packages built successfully! (All logs)

• spdlog/1.9.1:
  All packages built successfully! (All logs)

• spdlog/1.9.2:
  All packages built successfully! (All logs)

• spdlog/1.8.5:
  All packages built successfully! (All logs)

[gegles]

FYI @RubenRBS, thx! 🙏🏻

[gegles]

@prince-chrismc? Anybody? Thanks!!

[prince-chrismc]

@gegles You need to be more patient :) This PR is already approved and you can see the bot has been very hard at work (running smoothly as melted butter)

[prince-chrismc]

I made prince-chrismc/conan-center-index-pending-review#1 because the bot merge rules do not match GitHub's UI and you can check on the status of all the pull requests

You can see you're in the "Ready to Merge" Section

[gegles]

@gegles You need to be more patient :) This PR is already approved and you can see the bot has been very hard at work (running smoothly as melted butter)

@prince-chrismc,

Ah, ah, patience is not my strong suite, but I'll try harder 😉.

Thanks for the link and info... I was just making sure things were progressing forward and wasn't quite sure where in the process things were. Now I can, thanks!

You guys are doing a phenomenal job! I am very impress by the rigor and quality of this whole process and the Conan community! Thanks for all your hard work!

Cheers. G.

[prince-chrismc]

Thanks for the link and info... I was just making sure things were progressing forward and wasn't quite sure where in the process things were. Now I can, thanks!

This has been a challenge for a long time, I used to be a very active contributor myself so I know first hand. The team is putting a ton of effort to really reach new heights. It warms our hearts to hear that its recognized 🥲

I started a thread with the team to see if we can surface this information so it's easier for new contributors, the internals of c3i have this info so we'll see what they think :)