configure

#!/bin/bash

true ${CC="gcc"}

rm -f config.mak2
rm -f config.h

echo > config.h
echo > config.mak2


for i in "$@"; do
    if [ "${i/FLAGS=//}" != "$i" ]; then 
        echo "$i" >> config.mak2
    fi
done

"$CC" -E -o /dev/null -x c - <<< '#include <linux/securebits.h>' || echo "#define SECUREBITS_WORKAROUND" >> config.h
"$CC" -E -o /dev/null -x c - <<< '#include <sys/signalfd.h>' || echo "#define SIGNALFD_WORKAROUND" >> config.h
"$CC" -E -o /dev/null -x c - <<< '#include <sys/capability.h>' || (
    echo 'NO_CAPABILITIES=1' >> config.mak2
    echo "#define NO_CAPABILITIES" >> config.h
    echo 
)
if [[ "$(printf '#define _GNU_SOURCE\n#include <sched.h>\nCLONE_NEWUSER\n' | "$CC" -E -x c - | tail -n 1)" == "CLONE_NEWUSER" ]]; then
    echo "#define CLONE_PARAMETERS_WORKAROUND" >> config.h
fi
if ! printf '#define _GNU_SOURCE\n#include <sched.h>\n' | "$CC" -E  -x c - | grep '\<setns\>'; then
    echo "#define NO_SETNS" >> config.h
fi
if ! printf '#define _GNU_SOURCE\n#include <unistd.h>\n' | "$CC" -E  -x c - | grep '\<execvpe\>'; then
    echo "#define NO_EXECVPE" >> config.h
fi
if ! printf '#define _GNU_SOURCE\n#include <sched.h>\n' | "$CC" -E  -x c - | grep '\<unshare\>'; then
    echo "#define NO_UNSHARE" >> config.h
fi
if ! printf '#define _GNU_SOURCE 1\n#include <sys/syscall.h>\nSYS_pivot_root' | "$CC" -E  -x c - | tail -n 1 | grep '^\s*0\?x\?[0-9]'; then
    echo "#define NO_PIVOTROOT" >> config.h
fi

echo "Configuration finished, wrote necessary workarounds to config.h"