allow libigl to be built as lib

[AndreyMlashkin]

Specify library name and version: libigl/2.3.0

This is also a good place to share with all of us why you are submitting this PR (specially if it is a new addition to ConanCenter): is it a dependency of other libraries you want to package? Are you the author of the library? Thanks!

---

• I've read the guidelines for contributing.
• I've followed the PEP8 style guides for Python code in the recipes.
• I've used the latest Conan client version.
• I've tried at least one configuration locally with the
  conan-center hook activated.

[AndreyMlashkin]

Relates to #5542

[conan-center-bot]

All green in build 1 (3ceaa246b698eed712c57a9bc143138536346466):

• libigl/2.3.0@:
  All packages built successfully! (All logs)

[AndreyMlashkin]

@jgsogo , there is no build with header_only=False, there are only five that are explicitly set it to True (which is default) and therefore marked as duplicated

[jgsogo]

@jgsogo , there is no build with header_only=False, there are only five that are explicitly set it to True (which is default) and therefore marked as duplicated

This is how it works: the CI adds another configuration with header_only=True if the option header_only is available in the recipe. So, if header_only=True is already the default, it will add that new configuration, but it will be already duplicated.

Use default header_only=False and it will generate all the configurations and it will add one more with header_only=True.

[Croydon]

This is how it works: the CI adds another configuration with header_only=True if the option header_only is available in the recipe. So, if header_only=True is already the default, it will add that new configuration, but it will be already duplicated.

Use default header_only=False and it will generate all the configurations and it will add one more with header_only=True.

Is that something that CCI could improve? Adding header_only=False when header_only is True by default? Feels like an unnecessary restriction

-> #7267