Issue: sci-libs/fflas-ffpack-2.4.3 fails to compile.
Discovered on: amd64 (internal ref: tinderbox)
This machine uses a clang/LLVM toolchain.
If you think that this issue is strictly related to clang/LLVM please block bug 408963. If you think that this issue is strictly related to the LLD linker, please block bug 731004.
This machine uses also GLIBC-2.32. If you think that this issue is strictly related to GLIBC please block bug 736174.
Created attachment 659266 [details]
build log and emerge --info
Created attachment 659268 [details]
*** Bug 741510 has been marked as a duplicate of this bug. ***
The problem here (and in #741510) is that somehow, when you built sci-libs/givaro, it became convinced that you were using gcc4, as determined by the AC_COMPILER_NAME macro in https://github.com/linbox-team/givaro/blob/master/macros/debug.m4.
As a result, the configure.ac for givaro (https://github.com/linbox-team/givaro/blob/master/configure.ac#L77) appends "-fabi-version=6" to its CXXFLAGS. That gets propagated to the fflas-ffpack and linbox builds, even when you're performing them with clang and not gcc. Since clang doesn't understand -fabi-version=6, those builds fail.
Do you have any record of your givaro build? It may have made a mistake in determining that your compiler was gcc4.