Document GNU libc lossage in listen_addr doc string

Systems using GNU libc such as Linux are frequently configured in a
way getaddrinfo(NULL, ...) put the IPv4 wildcard "0.0.0.0" *before*
the IPv6 wildcard "::" in the result.  Because of that, listen_addr ""
listens only on all IPv4 addresses.  Workaround: listen_addr "::".

Document it in listen_addr's doc string.

diff --git a/include/econfig-spec.h b/include/econfig-spec.h
index 1cfa8b148161d76fb9e8fc61baf787ddf1a24073..6935ed7eb185626cef104cccb397445df2de31db 100644 (file)
--- a/include/econfig-spec.h
+++ b/include/econfig-spec.h
@@ -88,7 +88,10 @@ EMPCF_COMMENT("# \"\" listens on all, localhost just on the loopback interface.\
     "# OpenBSD restriction: when the system has both IPv4 and IPv6\n"
     "# addresses configured, \"\" listens on all IPv4 addresses, and \"::\"\n"
     "# on all IPv6 addresses.  There is no way to listen both on all IPv4\n"
     "# OpenBSD restriction: when the system has both IPv4 and IPv6\n"
     "# addresses configured, \"\" listens on all IPv4 addresses, and \"::\"\n"
     "# on all IPv6 addresses.  There is no way to listen both on all IPv4\n"

-    "# and on all IPv6 interfaces.")
+    "# and on all IPv6 interfaces.\n"
+    "# Systems using GNU libc such as Linux are frequently configured in a\n"
+    "# way that makes listen_addr "" listen only on all IPv4 addresses.\n"
+    "# You need to use \"::\" to listen on all IPv4 and IPv6 addresses.")

 EMPCFBOTH("port", loginport, char *, NSC_STRING, KM_INTERNAL,
     "TCP port the server will bind")
 EMPCFBOTH("keep_journal", keep_journal, int, NSC_INT, KM_INTERNAL,
 EMPCFBOTH("port", loginport, char *, NSC_STRING, KM_INTERNAL,
     "TCP port the server will bind")
 EMPCFBOTH("keep_journal", keep_journal, int, NSC_INT, KM_INTERNAL,