commit d8e7fe6

In README.md, document how to add -lrt to make (for older distributions).

 1@@ -58,12 +58,19 @@ Run `make` and then `make install` as root.
 2 
 3 If you're compiling on NetBSD, you should use the specific provided Makefile and run `make -f Makefile.NetBSD` and then `make -f Makefile.NetBSD install` as root.
 4 
 5+
 6 From version 2.27, `snac` includes support for the Mastodon API; if you are not interested on it, you can compile it out by running
 7 
 8 ```sh
 9 make CFLAGS=-DNO_MASTODON_API
10 ```
11 
12+If your compilation process complains about undefined references of `shm_open()` and `shm_unlink()` (it happens, for example, on 20.04.6 LTS), you need to tell `make` to add the `rt` library to the final linking command as follows:
13+
14+```sh
15+make LDFLAGS=-lrt
16+```
17+
18 See the administrator manual on how to proceed from here.
19 
20 ## Testing via Docker