avr-toolchain-5.5.0 fails to build. It seems to be mixing headers from GCC 5 and GCC 7:
--8<---------------cut here---------------start------------->8--- In file included from /gnu/store/rn75fm7adgx3pw5j8pg3bczfqq1y17lk-gcc-7.5.0/include/c++/stdlib.h:36:0, from ../../gcc-5.5.0/libcpp/system.h:214, from ../../gcc-5.5.0/libcpp/directives.c:22: /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:118:11: error: ‘::div_t’ has not been declared using ::div_t; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:119:11: error: ‘::ldiv_t’ has not been declared using ::ldiv_t; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:121:11: error: ‘::abort’ has not been declared using ::abort; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:122:11: error: ‘::abs’ has not been declared using ::abs; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:123:11: error: ‘::atexit’ has not been declared using ::atexit; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:129:11: error: ‘::atof’ has not been declared using ::atof; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:130:11: error: ‘::atoi’ has not been declared using ::atoi; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:131:11: error: ‘::atol’ has not been declared using ::atol; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:132:11: error: ‘::bsearch’ has not been declared using ::bsearch; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:133:11: error: ‘::calloc’ has not been declared using ::calloc; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:134:11: error: ‘::div’ has not been declared using ::div; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:135:11: error: ‘::exit’ has not been declared using ::exit; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:136:11: error: ‘::free’ has not been declared using ::free; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:137:11: error: ‘::getenv’ has not been declared using ::getenv; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:138:11: error: ‘::labs’ has not been declared using ::labs; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:139:11: error: ‘::ldiv’ has not been declared using ::ldiv; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:140:11: error: ‘::malloc’ has not been declared using ::malloc; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:142:11: error: ‘::mblen’ has not been declared using ::mblen; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:143:11: error: ‘::mbstowcs’ has not been declared using ::mbstowcs; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:144:11: error: ‘::mbtowc’ has not been declared using ::mbtowc; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:146:11: error: ‘::qsort’ has not been declared using ::qsort; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:152:11: error: ‘::rand’ has not been declared using ::rand; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:153:11: error: ‘::realloc’ has not been declared using ::realloc; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:154:11: error: ‘::srand’ has not been declared using ::srand; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:155:11: error: ‘::strtod’ has not been declared using ::strtod; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:156:11: error: ‘::strtol’ has not been declared using ::strtol; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:157:11: error: ‘::strtoul’ has not been declared using ::strtoul; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:158:11: error: ‘::system’ has not been declared using ::system; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:160:11: error: ‘::wcstombs’ has not been declared using ::wcstombs; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:161:11: error: ‘::wctomb’ has not been declared using ::wctomb; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:168:10: error: ‘ldiv_t’ does not name a type inline ldiv_t ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:214:11: error: ‘::lldiv_t’ has not been declared using ::lldiv_t; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:220:11: error: ‘::_Exit’ has not been declared using ::_Exit; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:224:11: error: ‘::llabs’ has not been declared using ::llabs; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:226:10: error: ‘lldiv_t’ does not name a type inline lldiv_t ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:230:11: error: ‘::lldiv’ has not been declared using ::lldiv; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:241:11: error: ‘::atoll’ has not been declared using ::atoll; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:242:11: error: ‘::strtoll’ has not been declared using ::strtoll; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:243:11: error: ‘::strtoull’ has not been declared using ::strtoull; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:245:11: error: ‘::strtof’ has not been declared using ::strtof; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:246:11: error: ‘::strtold’ has not been declared using ::strtold; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:254:22: error: ‘__gnu_cxx::lldiv_t’ has not been declared using ::__gnu_cxx::lldiv_t; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:256:22: error: ‘__gnu_cxx::_Exit’ has not been declared using ::__gnu_cxx::_Exit; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:258:22: error: ‘__gnu_cxx::llabs’ has not been declared using ::__gnu_cxx::llabs; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:259:22: error: ‘__gnu_cxx::div’ has not been declared using ::__gnu_cxx::div; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:260:22: error: ‘__gnu_cxx::lldiv’ has not been declared using ::__gnu_cxx::lldiv; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:262:22: error: ‘__gnu_cxx::atoll’ has not been declared using ::__gnu_cxx::atoll; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:263:22: error: ‘__gnu_cxx::strtof’ has not been declared using ::__gnu_cxx::strtof; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:264:22: error: ‘__gnu_cxx::strtoll’ has not been declared using ::__gnu_cxx::strtoll; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:265:22: error: ‘__gnu_cxx::strtoull’ has not been declared using ::__gnu_cxx::strtoull; ^ /gnu/store/6wn346cbw1mh6264v426pwj2klgvxr0z-gcc-5.5.0/include/c++/cstdlib:266:22: error: ‘__gnu_cxx::strtold’ has not been declared using ::__gnu_cxx::strtold; ^ In file included from ../../gcc-5.5.0/libcpp/system.h:214:0, from ../../gcc-5.5.0/libcpp/directives.c:22: /gnu/store/rn75fm7adgx3pw5j8pg3bczfqq1y17lk-gcc-7.5.0/include/c++/stdlib.h:38:12: error: ‘std::abort’ has not been declared using std::abort; ^ /gnu/store/rn75fm7adgx3pw5j8pg3bczfqq1y17lk-gcc-7.5.0/include/c++/stdlib.h:39:12: error: ‘std::atexit’ has not been declared using std::atexit; ^ /gnu/store/rn75fm7adgx3pw5j8pg3bczfqq1y17lk-gcc-7.5.0/include/c++/stdlib.h:40:12: error: ‘std::exit’ has not been declared using std::exit; ^ /gnu/store/rn75fm7adgx3pw5j8pg3bczfqq1y17lk-gcc-7.5.0/include/c++/stdlib.h:51:12: error: ‘std::div_t’ has not been declared using std::div_t; ^ /gnu/store/rn75fm7adgx3pw5j8pg3bczfqq1y17lk-gcc-7.5.0/include/c++/stdlib.h:52:12: error: ‘std::ldiv_t’ has not been declared using std::ldiv_t; ^ /gnu/store/rn75fm7adgx3pw5j8pg3bczfqq1y17lk-gcc-7.5.0/include/c++/stdlib.h:55:12: error: ‘std::atof’ has not been declared using std::atof; ^ /gnu/store/rn75fm7adgx3pw5j8pg3bczfqq1y17lk-gcc-7.5.0/include/c++/stdlib.h:56:12: error: ‘std::atoi’ has not been declared using std::atoi; --8<---------------cut here---------------end--------------->8--- -- Ricardo