This file contains any messages produced by compilers while running configure, to aid debugging if configure makes a mistake. configure:527: checking for gcc configure:604: checking whether the C compiler (x86_64-pc-linux-gnu-clang -O2 -pipe -march=x86-64 -frecord-gcc-switches -fno-diagnostics-color -fmessage-length=0 -Wl,-O1 -Wl,--as-needed -Wl,--defsym=__gentoo_check_ldflags__=0 -fuse-ld=lld) works configure:618: x86_64-pc-linux-gnu-clang -o conftest -O2 -pipe -march=x86-64 -frecord-gcc-switches -fno-diagnostics-color -fmessage-length=0 -Wl,-O1 -Wl,--as-needed -Wl,--defsym=__gentoo_check_ldflags__=0 -fuse-ld=lld conftest.c 1>&5 configure:615:1: warning: type specifier missing, defaults to 'int' [-Wimplicit-int] main(){return(0);} ^ 1 warning generated. configure:638: checking whether the C compiler (x86_64-pc-linux-gnu-clang -O2 -pipe -march=x86-64 -frecord-gcc-switches -fno-diagnostics-color -fmessage-length=0 -Wl,-O1 -Wl,--as-needed -Wl,--defsym=__gentoo_check_ldflags__=0 -fuse-ld=lld) is a cross-compiler configure:643: checking whether we are using GNU C configure:652: x86_64-pc-linux-gnu-clang -E conftest.c configure:667: checking whether x86_64-pc-linux-gnu-clang accepts -g configure:699: checking for c++ configure:730: checking whether the C++ compiler (x86_64-pc-linux-gnu-clang++ -O2 -pipe -march=x86-64 -frecord-gcc-switches -fno-diagnostics-color -fmessage-length=0 -Wl,-O1 -Wl,--as-needed -Wl,--defsym=__gentoo_check_ldflags__=0 -fuse-ld=lld) works configure:744: x86_64-pc-linux-gnu-clang++ -o conftest -O2 -pipe -march=x86-64 -frecord-gcc-switches -fno-diagnostics-color -fmessage-length=0 -Wl,-O1 -Wl,--as-needed -Wl,--defsym=__gentoo_check_ldflags__=0 -fuse-ld=lld conftest.C 1>&5 configure:741:1: error: C++ requires a type specifier for all declarations main(){return(0);} ^ 1 error generated. configure: failed program was: #line 740 "configure" #include "confdefs.h" main(){return(0);}