https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67728
--- Comment #8 from Andrew Roberts <andrewm.roberts at sky dot com> --- The initial bug report was for cross compiling. Bug 70211 is for native builds on ARM. Given the huge growth in ARM development boards, this needs at least documenting. As with the original reporter I spent ages trying to figure this out before stumbling across a solution (and the solution isn't to build GMP out of tree either). Building GMP out of tree creates another can of worms (esp on multiarch machines). Any documentation fix should mention the targets that need the change (ARM), and that both cross and native builds are affected. Also reference the undefined symbol __gmpn_invert_limb so people know they have run across it. Once you do the above it sort of becomes obvious that actually building GMP intree with the correct CPU instead of none is proper solution. Or does that not work for cross compilies? The easier it is for people to build gcc themselves the more testing prelease versions will get.
