How to compile with --enable-nanorc?

Hello, I compiled nano (v 2.9 bcause it's not available on debian stretch)
and by default nanorc is not read which was very surprising.

So I tried to fix it by recompiling like that:
./configure --enable-nanorc --enable-color --enable-multibuffer
--sysconfdir=/etc --prefix=/usr
make
make install

Also tried other variants, but the result is that /etc/nanorc is never read

strace -fe trace=open nano /etc/nanorc
open("/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libncursesw.so.5", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libtinfo.so.5", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
open("/lib/x86_64-linux-gnu/libdl.so.2", O_RDONLY|O_CLOEXEC) = 3
open("/usr/lib/locale/locale-archive", O_RDONLY|O_CLOEXEC) = 3
open("/usr/lib/x86_64-linux-gnu/gconv/gconv-modules.cache", O_RDONLY) = 3
open("/lib/terminfo/s/screen-256color", O_RDONLY) = 3
+++ exited with 0 +++

What should I do???

thank you