Document example failure of glibc static linking with NSS somewhere

I got this example segfault of somebody trying to use an executable statically linked with glibc and using the network.

The stacktrace is of the program crashing in `gdb`; `stack build ... --no-strip` was used to obtain a sensible stack trace, otherwise it would show just `in ?? ()` in the entire trace.

```
Thread 11 "myprogram:w" received signal SIGSEGV, Segmentation fault.
[Switching to LWP 494]
0x00007ffff43857a0 in internal_getent (stream=stream@entry=0x7ffff4059680, result=result@entry=0x368b1a0 , buffer=buffer@entry=0x36e7a20 "# Internet (IP) protocols\n", buflen=buflen@entry=1024, errnop=errnop@entry=0x7fffe67fc6a0)
at nss_files/files-XXX.c:216
216 nss_files/files-XXX.c: No such file or directory.
(gdb) bt
#0 0x00007ffff43857a0 in internal_getent (stream=stream@entry=0x7ffff4059680, result=result@entry=0x368b1a0 , buffer=buffer@entry=0x36e7a20 "# Internet (IP) protocols\n", buflen=buflen@entry=1024, errnop=errnop@entry=0x7fffe67fc6a0)
at nss_files/files-XXX.c:216
#1 0x00007ffff4385a32 in _nss_files_getprotobyname_r (name=0x420021c800 "tcp", result=0x368b1a0 , buffer=0x36e7a20 "# Internet (IP) protocols\n", buflen=1024, errnop=0x7fffe67fc6a0) at nss_files/files-proto.c:38
#2 0x0000000003026f47 in getprotobyname_r ()
#3 0x0000000003026d18 in getprotobyname ()
#4 0x0000000002208aee in ?? ()
#5 0x0000000000000000 in ?? ()
```

Should probably document that somewhere as an example for why you may want to use musl here.