Dante's packaging design has some very pretty macro usage, but also fragile.

The error & getaddrinfo error checking tries to expand a macro outside a
string, leading to it expanding empty in some cases. Quoting the string makes
it show up as expected.

```
checking getaddrinfo() error symbols... configure: error: in `/var/tmp/portage/net-proxy/dante-1.4.3/work/dante-1.4.3':
configure: error: error: getaddrinfo() error value count too low
See `config.log' for more details`
```

--- dante-1.4.3//acinclude.m4	2017-01-23 11:28:08.000000000 -0800
+++ dante-1.4.3//acinclude.m4	2024-11-17 19:51:39.398597593 -0800
@@ -1110,7 +1114,7 @@
        [AC_LANG_PROGRAM([[#include <errno.h>]],
                         [[
 #ifdef $3
-errnoval: $3
+"errnoval: $3"
 #else
 #error "errno value $3 not defined"
 #endif]])],
@@ -1134,7 +1138,7 @@
 #include <netdb.h>]],
                         [[
 #ifdef $3
-gaierrval: $3
+"gaierrval: $3"
 #else
 #error "gai error value $3 not defined"
 #endif]])],