Just dynamically link to GSL, don't distribute GSL with your app, and you'll be fine. Most of your colleagues would have it installed on their computers anyway...
I'm not a lawyer but my understanding is that dynamic linking doesn't get you around having to use a GPL compatible license if you link to the library [1][2] and distribute your code to others. That is why GNU releases the standard c libraries as LGPL rather than GPL so you can link to them without having to be GPL compatible yourself.
I personally would appreciate it if the GSL went to LGPL. I have certainly been in situations where an employer wasn't ready to release their source code under GPL but would have sponsored me to add new functionality to GSL if we could link to it under LGPL. That said I can understand the reasons the authors went straight GPL and really appreciate all the amazing work they've done as it is a really nice library with a lot of functionality and pretty solid documentation the times I've used it.
I personally would appreciate it if the GSL went to LGPL. I have certainly been in situations where an employer wasn't ready to release their source code under GPL but would have sponsored me to add new functionality to GSL if we could link to it under LGPL. That said I can understand the reasons the authors went straight GPL and really appreciate all the amazing work they've done as it is a really nice library with a lot of functionality and pretty solid documentation the times I've used it.
[1] http://www.gnu.org/licenses/why-not-lgpl.en.html [2] http://stackoverflow.com/questions/1114045/gpl-and-lgpl-open...