I’m not sure which reason or for what! :)
The issue I see is that on this standard Ubuntu:
krzysztof@hagrid:~/packages/math-compare$ cat /proc/version
Linux version 4.10.0-33-generic (buildd@lgw01-52) (gcc version 6.3.0 20170406 (Ubuntu 6.3.0-12ubuntu2) ) #37-Ubuntu SMP Fri Aug 11 10:55:28 UTC 2017
If the math library tests build with
stdlib=libc++, gtest can’t find two headers:
bits/c++config.h, if I add the
-I to include those from the stdlib, it also finds conflicting implementations of other stuff and fails. If I set it to use the
libstdc++ instead of
libc++ then clang and g++ work fine. What I’m missing is what problem is caused by Travis if you let the system pick it’s standard library (omit the
-stdlib flag.). I could see this being touchy since Ubuntu manages it using the
update-alternatives symlinks and there’s a pretty wide range of combinations available when it comes to c++ compilers and it does seem like an Ubuntu bug.
libc++ library goes through quite a bit of macro gymnastics to get all this right in its own build so I don’t have much hope for us having a simple solution (travis or no travis).