For some reason their configuration script thinks "--with-gmp*" means the build should have GMP, even if you pass --with-gmp=no, so the best thing is to not mention GMP at all if the use flag is not enabled, see attached patch. Reproducible: Always Steps to Reproduce: USE="-gmp" emerge =sci-mathematics/z3-4.3.1 Actual Results: See build.log Expected Results: It should emerge z3.
Created attachment 456138 [details] Failed build log This is after applying the fix from bug 602498
Created attachment 456140 [details, diff] Patch that fixes the problem
I added z3 with the fixes, thanks, to portage. As z3 is required by sci-mathematics/isabelle. commit e1bee0588417636345663574e7c1ef127abbebe6 Author: Mark Wright <gienah@gentoo.org> Date: Mon Jan 2 11:18:51 2017 +1100 sci-mathematics/z3: Thanks to Yichao Zhou, jlec and slyfox for development on the z3 ebuilds. Thanks to David E. Narv?ez for reporting and patching. Gentoo-bug: 602498, 602600