devel/linux-*-devtools: remove GMP
With GMP in linux_base-* remove its occurrence in the devtools port.
Spotted by: antoine
Differential Revision: https://reviews.freebsd.org/D1256
Approved by: swills (mentor)
Development tools and base libraries for linux_base-f10. Required by
some Linux applications such as Matlab, which allows the user to integrate
custom C, C++, and Fortran code via the MEX compiler.
Submitted by: Jason Bacon <jwbacon (at) tds.net>