(chroot) livecd /usr/src/linux # make && make modules_install
  CALL    scripts/checksyscalls.sh
  DESCEND  objtool
In file included from <stdin>:1:
/usr/include/libelf/libelf.h:28:5: error: "__LIBELF_INTERNAL__" is not defined, evaluates to 0 [-Werror=undef]
 #if __LIBELF_INTERNAL__
     ^~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
  CC       /usr/src/linux-4.19.66-gentoo/tools/objtool/arch/x86/decode.o
In file included from arch/x86/../../elf.h:22,
                 from arch/x86/decode.c:26:
/usr/include/libelf/gelf.h:25:5: error: "__LIBELF_INTERNAL__" is not defined, evaluates to 0 [-Werror=undef]
 #if __LIBELF_INTERNAL__
     ^~~~~~~~~~~~~~~~~~~
In file included from arch/x86/../../elf.h:22,
                 from arch/x86/decode.c:26:
/usr/include/libelf/gelf.h:31:5: error: "__LIBELF_NEED_LINK_H" is not defined, evaluates to 0 [-Werror=undef]
 #if __LIBELF_NEED_LINK_H
     ^~~~~~~~~~~~~~~~~~~~
/usr/include/libelf/gelf.h:33:7: error: "__LIBELF_NEED_SYS_LINK_H" is not defined, evaluates to 0 [-Werror=undef]
 #elif __LIBELF_NEED_SYS_LINK_H
       ^~~~~~~~~~~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
mv: cannot stat '/usr/src/linux-4.19.66-gentoo/tools/objtool/arch/x86/.decode.o.tmp': No such file or directory
make[4]: *** [/usr/src/linux-4.19.66-gentoo/tools/build/Makefile.build:97: /usr/src/linux-4.19.66-gentoo/tools/objtool/arch/x86/decode.o] Error 1
make[3]: *** [/usr/src/linux-4.19.66-gentoo/tools/build/Makefile.build:139: arch/x86] Error 2
make[2]: *** [Makefile:50: /usr/src/linux-4.19.66-gentoo/tools/objtool/objtool-in.o] Error 2
make[1]: *** [Makefile:63: objtool] Error 2
make: *** [Makefile:1646: tools/objtool] Error 2