ENABLE_NLS not defined Localization not working #429

Localization is not compiled in because ENABLE_NLS is not defined in src/main.c

#ifdef ENABLE_NLS
    bindtextdomain(PACKAGE, PACKAGE_LOCALE_DIR);
    bind_textdomain_codeset(PACKAGE, "UTF-8");
    textdomain(PACKAGE);
#endif

The issue was verified on stock Ubuntu 26 LTS version 2.4-2 deb package, probably in many other distributions as well
and on the latest 2.6.10-da72 build see attached screenshots.

In the about window the localization is in fact working on gnome system dialogs.

May i open a different PR from the existing #421 with minimal changes and without additional packages?

There is just a little error in configure.ac to be fixed for this issue.

Sorry for the screenshot sizes, i just found out that they are 4k.

It seems GTK3 scaling works well within Gpredict.