On Wed, 20 Sep 2017 13:44:59 +0300 Petr Ovtchenkov <p...@void-ptr.info> wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71212 > > On Fri, 20 May 2016 16:10:50 +0300 > Petr Ovtchenkov <p...@void-ptr.info> wrote: > > > Some old ad-hoc (adding -I/usr/include to compiler > > flags) break compilation of libstdc++ for foreign > > target architecture (due to compiler see includes > > of native). Reference for terms: https://gcc.gnu.org/onlinedocs/gccint/Configure-Terms.html Present of "CANADIAN=yes" lead to inclusion of headers from build (-I/usr/include). "CANADIAN=yes" used _only_ to set "-I/usr/include". Inclusion of build headers in cross-compilation process is not a mistake only in case of native (i.e. it is mistake for cross, for canadian, for crossed native and for crossback), but sometimes give "success". Note, that build/host/target may be different not only due to different architectures, but due to different sysroots (libc, kernel, binutils, etc.). CANADIAN is set to "yes" by code - # If Canadian cross, then don't pick up tools from the build directory. - # Used only in GLIBCXX_EXPORT_INCLUDES. - if test -n "$with_cross_host" && - test x"$build_alias" != x"$with_cross_host" && - test x"$build" != x"$target"; - then - CANADIAN=yes - else - CANADIAN=no - fi and it add "-I/usr/include" to compiler flags for building libstdc++. This is wrong. Reference to patch: https://gcc.gnu.org/ml/gcc-patches/2017-09/msg01332.html