Because of a library I use I get loads of warnings. But when adding -Wdeprecated-declarations to the compiler additional options, the warnings still appear. How can I add this option to the compiler?
The exact location of the setting depends on your project type. Please see this page for more details. You can also double-check whether the option gets actually passed to the compiler by enabling verbose build (see project type-specific pages linked above) and rechecking the GCC command lines.