Allow configuring GSL library use

[AnthonyVH]

I am working on a project which uses ms-gsl all throughout its codebase. Unfortunately this clashes with gsl-lite which is used in mp-units. I.e. I'd like to adopt the use of mp-units, but can't right now because of this.

As far as I can see gsl-lite is only used for the expect and assert functionality it provides.

Would it be possible to either:

• Allow disabling these checks & assertions (i.e. no dependency on gsl-lite at all in that case)
• Make it configurable which GSL library will be used (and fall back on gsl-lite)

[mpusz]

Hi @AnthonyVH, thanks for the excellent feedback. I will try to provide such a customization soon.

[AnthonyVH]

Wow, that was extremely fast. Thanks a lot!