Improve portability about c-edit

[velorek1]

Interesting, I didn't know about this. I'll look into it and see what I can do.
Also, feel free to modify it yourself if you feel like doing it.
Thank you for your comment!

[catafest]

I try to build with make on Fedora 33 :

[mythcat@desk src]$ make
cc -Wall -Wextra -fsigned-char    -c -o main.o main.c
cc -Wall -Wextra -fsigned-char    -c -o rterm.o rterm.c
cc -Wall -Wextra -fsigned-char    -c -o listc.o listc.c
cc -Wall -Wextra -fsigned-char    -c -o scbuf.o scbuf.c
cc -Wall -Wextra -fsigned-char    -c -o opfile.o opfile.c
cc -Wall -Wextra -fsigned-char    -c -o uintf.o uintf.c
cc -Wall -Wextra -fsigned-char    -c -o fileb.o fileb.c
cc -Wall -Wextra -fsigned-char    -c -o keyb.o keyb.c
cc -Wall -Wextra -fsigned-char    -c -o tm.o tm.c
cc  -o cedit main.o rterm.o listc.o scbuf.o opfile.o uintf.o fileb.o keyb.o tm.o 
/bin/ld: scbuf.o:(.bss+0x30): multiple definition of `rows'; main.o:(.bss+0x112aa30): first defined here
/bin/ld: scbuf.o:(.bss+0x34): multiple definition of `columns'; main.o:(.bss+0x112aa34): first defined here
collect2: error: ld returned 1 exit status

[mythcat@desk src]$ make -v
GNU Make 4.3
Built for x86_64-redhat-linux-gnu
Copyright (C) 1988-2020 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

[velorek1]

I see, I've changed some variable names to avoid these conflicts.
It should work fine now.
(Mind due, it is still a demo version)
Thank you for letting me know.