reserved identifier violation

[Markus Elfring]

Hello,

I would like to point out that identifiers like “_READLINE_H_” and
“_COLORS_H_” do eventually not fit to the expected naming convention of
the C++ language standard.
Would you like to adjust your selection for unique names?
https://wiki.sei.cmu.edu/confluence/display/cplusplus/DCL51-CPP.+Do+not+declare+or+define+a+reserved+identifier#DCL51CPP.Donotdeclareordefineareservedidentifier-NoncompliantCodeExample%28HeaderGuard%29

https://git.savannah.gnu.org/cgit/readline.git/tree/readline.h?id=7274faabe97ce53d6b464272d7e6ab6c1392837b#n22
https://git.savannah.gnu.org/cgit/readline.git/tree/colors.h?id=7274faabe97ce53d6b464272d7e6ab6c1392837b#n27

Regards,
Markus