https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109926
--- Comment #11 from cqwrteur <unlvsur at live dot com> --- (In reply to cqwrteur from comment #10) > (In reply to Jonathan Wakely from comment #8) > > Comment on attachment 55135 [details] > > config > > > > configure:18893: checking fenv.h usability > > configure:18893: i586-msdosdjgpp-c++ -c -g -O2 -std=c++11 > > -fno-exceptions conftest.cpp >&5 > > configure:18893: $? = 0 > > configure:18893: result: yes > > configure:18893: checking fenv.h presence > > configure:18893: i586-msdosdjgpp-c++ -E conftest.cpp > > configure:18893: $? = 0 > > configure:18893: result: yes > > configure:18893: checking for fenv.h > > configure:18893: result: yes > > > > This means configure is finding fenv.h in your sysroot. > > i586-msdosdjgpp-c++ should use i586-msdosdjgpp-gcc to test, not > i586-msdosdjgpp-c++ i think https://github.com/gcc-mirror/gcc/blob/6fc84f680d098f82c1c43435fdb206099f0df4df/libstdc%2B%2B-v3/configure#L19263 my guess is that it tries to use detect it by using the cross toolchain's libstdc++ fenv.h despite fenv.h does not exist. probably need to detect it with -nostdinc++??
