Make setproctitle() available in 0.2 and 0.5 version nodes

Make the 0.5 version the default, so that code wanting the actual
implemented version can get a proper versioned depdendency. For code
linked against the old version, make it available as an alias.

src/libbsd.map

@@ -73,8 +73,6 @@ LIBBSD_0.2 {
     pidfile_close;
     pidfile_remove;
 
-    setproctitle;
-
     arc4random_buf;
     arc4random_uniform;
 } LIBBSD_0.1;
@@ -99,6 +97,9 @@ LIBBSD_0.5 {
     fgetwln;
     fparseln;
 
+    /* Introduced in 0.2 as a stub, implemented in 0.5. */
+    setproctitle;
+
     strnstr;
 
     wcslcat;