include locale.h for setlocale()
This issue is surfaced on musl systems+clang
Fixes
../gnome-console-47.0/src/main.c:29:3: error: call to undeclared function 'setlocale'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
29 | setlocale (LC_ALL, "");
| ^
../gnome-console-47.0/src/main.c:29:14: error: use of undeclared identifier 'LC_ALL'
29 | setlocale (LC_ALL, "");
| ^
2 errors generated.
Edited by Khem Raj