-Werror is redundant because CMake not only checks the exit status, but also parses the output of try_compile. -Wformat-security is a special case, because specifying it without -Wformat causes gcc to emit a warning in a format not recognized by CMake, which makes the check pass.

-Werror is redundant because CMake not only checks the exit status, but also parses the output of try_compile. -Wformat-security is a special case, because specifying it without -Wformat causes gcc to emit a warning in a format not recognized by CMake, which makes the check pass.

-Werror is redundant because CMake not only checks the exit status, but also parses the output of try_compile. -Wformat-security is a special case, because specifying it without -Wformat causes gcc to emit a warning in a format not recognized by CMake, which makes the check pass.