duplicate symbols link failure caused by not using extern in headers

[todd-richmond]

gcc 12 (and likely earlier compilers) fail attempting to link ag due to duplicate symbols. This is caused because structs are defined in .h files which get included into multiple .c files. The solution is to use extern foo bar; in the .h and then define in a single .c

The list includes opts, print_mtx, out_fd, stats and a slew of others

For those who need a workaround you can set LDFLAGS to "-z muldefs"

[Try2Code]

thx so much for this post 🙏 @todd-richmond