IT’S MY MISTAKE…
After cleaning everything all, my building process was successfully… 
Best regards…
Thanks for your guide, Fox_exe…
Compared to the previous gen1, it’s too hard to build a package from scratch… 
At first, I downloaded the GPL Source Code having same version for my device(v2.21.119).
I installed Debian v8.7.1 32bit in my virtual box, and then built the cross-compile environment…
As a test, I compiled an rsync program that seems to be the simplest, moved it to my WDMC and executed it successfully. 
I choiced the nano program in Open_Source_packages for the second try…
However, the following error has occurred when building with “–enable-utf8”:
[The error part is quoted (full messages is attached) ]
(snipped)
configure: WARNING:
*** No curses lib available. Consider getting the official ncurses
*** distribution from ftp://ftp.gnu.org/pub/gnu/ncurses if you get
*** errors compiling nano.
checking for use_default_colors in -l… no
configure: error:
*** UTF-8 support was requested, but insufficient UTF-8 support was
*** detected in your curses and/or C libraries. Please verify that your
*** slang was built with UTF-8 support or your curses was built with
*** wide character support, and that your C library was built with wide
*** character support.
make: *** No targets specified and no makefile found. Stop.
make: *** No rule to make target ‘install’. Stop.
I thought the ncurses first…
then, tried to compile the ncurses, but also got an error.
[The error part is quoted (full messages is attached) ]
(snipped)
arm-mv5sft-linux-gnueabi-gcc -DHAVE_CONFIG_H -I…/ncurses -I. -I. -I…/include -D_GNU_SOURCE -D_FILE_OFFSET_BITS=64 -DNDEBUG -I/home/roy/DNS-345_GPL/packages/ncurses-5.7/_install/include/ncurses -O2 --param max-inline-insns-single=1200 -c …/ncurses/./tty/hardscroll.c -o …/objects/hardscroll.o
make[1]: arm-mv5sft-linux-gnueabi-gcc: Command not found
Makefile:680: recipe for target ‘…/objects/hardscroll.o’ failed
make[1]: *** […/objects/hardscroll.o] Error 127
make[1]: Leaving directory ‘/work/WD_MyCloud_GPL_v2.21.119_20160901/Open_Source_packages/ncurses-5.7/ncurses’
Makefile:98: recipe for target ‘install’ failed
make: *** [install] Error 2
How could I solve these errors? 
Thanks in advance…
Best regards,
full_error_messages_for_nano.txt (5.8 KB)
full_error_messages_for_ncurses.txt (119.9 KB)
