https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81797
Misty De Meo <misty at brew dot sh> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |misty at brew dot sh --- Comment #3 from Misty De Meo <misty at brew dot sh> --- I'm seeing a similar failure, also on macOS 10.13. I can only reproduce when macOS is installed on an APFS filesystem, not HFS+. The issue occurs intermittently, and the specific header that libstdc++ fails to find varies from run to run. /private/tmp/gcc-20170815-16334-85805x/gcc-7.2.0/build/./gcc/xgcc -shared-libgcc -B/private/tmp/gcc-20170815-16334-85805x/gcc-7.2.0/build/./gcc -nostdinc++ -L/private/tmp/gcc-20170815-16334-85805x/gcc-7.2.0/build/x86_64-apple-darwin17.0.0/libstdc++-v3/src -L/private/tmp/gcc-20170815-16334-85805x/gcc-7.2.0/build/x86_64-apple-darwin17.0.0/libstdc++-v3/src/.libs -L/private/tmp/gcc-20170815-16334-85805x/gcc-7.2.0/build/x86_64-apple-darwin17.0.0/libstdc++-v3/libsupc++/.libs -B/usr/local/Cellar/gcc/7.2.0/x86_64-apple-darwin17.0.0/bin/ -B/usr/local/Cellar/gcc/7.2.0/x86_64-apple-darwin17.0.0/lib/ -isystem /usr/local/Cellar/gcc/7.2.0/x86_64-apple-darwin17.0.0/include -isystem /usr/local/Cellar/gcc/7.2.0/x86_64-apple-darwin17.0.0/sys-include -x c++-header -nostdinc++ -g -O2 -I/private/tmp/gcc-20170815-16334-85805x/gcc-7.2.0/build/x86_64-apple-darwin17.0.0/libstdc++-v3/include/x86_64-apple-darwin17.0.0 -I/private/tmp/gcc-20170815-16334-85805x/gcc-7.2.0/build/x86_64-apple-darwin17.0.0/libstdc++-v3/include -I/private/tmp/gcc-20170815-16334-85805x/gcc-7.2.0/libstdc++-v3/libsupc++ -O2 -g /private/tmp/gcc-20170815-16334-85805x/gcc-7.2.0/libstdc++-v3/include/precompiled/stdc++.h -o x86_64-apple-darwin17.0.0/bits/stdc++.h.gch/O2g.gch In file included from /private/tmp/gcc-20170815-16334-85805x/gcc-7.2.0/build/x86_64-apple-darwin17.0.0/libstdc++-v3/include/sstream:38:0, from /private/tmp/gcc-20170815-16334-85805x/gcc-7.2.0/build/x86_64-apple-darwin17.0.0/libstdc++-v3/include/complex:45, from /private/tmp/gcc-20170815-16334-85805x/gcc-7.2.0/build/x86_64-apple-darwin17.0.0/libstdc++-v3/include/ccomplex:39, from /private/tmp/gcc-20170815-16334-85805x/gcc-7.2.0/libstdc++-v3/include/precompiled/stdc++.h:52: /private/tmp/gcc-20170815-16334-85805x/gcc-7.2.0/build/x86_64-apple-darwin17.0.0/libstdc++-v3/include/istream:38:10: fatal error: ios: No such file or directory #include <ios> ^~~~~ I can confirm that $target/libstdc++-v3/include/ios exists.