package/dhcp: fix build with gcc 10

Fixes:
 - http://autobuild.buildroot.org/results/82df44b20ba4ecfb8cf7d077247b3262647a572d

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/dhcp/0001-WIP-Resolve-ISC-DHCP-does-not-build-with-gcc10.patch

@@ -0,0 +1,121 @@
+From 129b7e402bd6e7278854e5a8935fce460552b5f4 Mon Sep 17 00:00:00 2001
+From: Thomas Markwalder <tmark@isc.org>
+Date: Thu, 30 Jul 2020 10:01:36 -0400
+Subject: [PATCH] [#117] Fixed gcc 10 compilation issues
+
+client/dhclient.c
+relay/dhcrelay.c
+    extern'ed local_port,remote_port
+
+common/discover.c
+    init local_port,remote_port to 0
+
+server/mdb.c
+    extern'ed dhcp_type_host
+
+server/mdb6.c
+    create_prefix6() - eliminated memcpy string overflow error
+
+[Retrieved from:
+https://gitlab.isc.org/isc-projects/dhcp/-/merge_requests/60/diffs?commit_id=129b7e402bd6e7278854e5a8935fce460552b5f4]
+Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
+---
+ RELNOTES          | 5 +++++
+ client/dhclient.c | 5 +++--
+ common/discover.c | 4 ++--
+ relay/dhcrelay.c  | 4 ++--
+ server/mdb.c      | 2 +-
+ server/mdb6.c     | 2 +-
+ 6 files changed, 14 insertions(+), 8 deletions(-)
+
+diff --git a/RELNOTES b/RELNOTES
+index 9d0a0414..6919dba7 100644
+--- a/RELNOTES
++++ b/RELNOTES
+@@ -103,6 +103,11 @@ ISC DHCP is open source software maintained by Internet Systems
+ Consortium.  This product includes cryptographic software written
+ by Eric Young (eay@cryptsoft.com).
+ 
++		Changes since 4.4.2 (Bug Fixes)
++
++- Minor corrections to allow compilation under gcc 10.
++  [Gitlab #117]
++
+ 		Changes since 4.4.2b1 (Bug Fixes)
+ 
+ - Added a clarification on DHCPINFORMs and server authority to
+diff --git a/client/dhclient.c b/client/dhclient.c
+index 189e5270..7a7837cb 100644
+--- a/client/dhclient.c
++++ b/client/dhclient.c
+@@ -83,8 +83,9 @@ static const char message [] = "Internet Systems Consortium DHCP Client";
+ static const char url [] = "For info, please visit https://www.isc.org/software/dhcp/";
+ #endif /* UNIT_TEST */
+ 
+-u_int16_t local_port = 0;
+-u_int16_t remote_port = 0;
++extern u_int16_t local_port;
++extern u_int16_t remote_port;
++
+ #if defined(DHCPv6) && defined(DHCP4o6)
+ int dhcp4o6_state = -1; /* -1 = stopped, 0 = polling, 1 = started */
+ #endif
+diff --git a/common/discover.c b/common/discover.c
+index ca4f4d55..22f09767 100644
+--- a/common/discover.c
++++ b/common/discover.c
+@@ -45,8 +45,8 @@ struct interface_info *fallback_interface = 0;
+ 
+ int interfaces_invalidated;
+ int quiet_interface_discovery;
+-u_int16_t local_port;
+-u_int16_t remote_port;
++u_int16_t local_port = 0;
++u_int16_t remote_port = 0;
+ u_int16_t relay_port = 0;
+ int dhcpv4_over_dhcpv6 = 0;
+ int (*dhcp_interface_setup_hook) (struct interface_info *, struct iaddr *);
+diff --git a/relay/dhcrelay.c b/relay/dhcrelay.c
+index 883d5058..7211e3bb 100644
+--- a/relay/dhcrelay.c
++++ b/relay/dhcrelay.c
+@@ -95,8 +95,8 @@ enum { forward_and_append,	/* Forward and append our own relay option. */
+        forward_untouched,	/* Forward without changes. */
+        discard } agent_relay_mode = forward_and_replace;
+ 
+-u_int16_t local_port;
+-u_int16_t remote_port;
++extern u_int16_t local_port;
++extern u_int16_t remote_port;
+ 
+ /* Relay agent server list. */
+ struct server_list {
+diff --git a/server/mdb.c b/server/mdb.c
+index ff8a707f..8266d764 100644
+--- a/server/mdb.c
++++ b/server/mdb.c
+@@ -67,7 +67,7 @@ static host_id_info_t *host_id_info = NULL;
+ 
+ int numclasseswritten;
+ 
+-omapi_object_type_t *dhcp_type_host;
++extern omapi_object_type_t *dhcp_type_host;
+ 
+ isc_result_t enter_class(cd, dynamicp, commit)
+ 	struct class *cd;
+diff --git a/server/mdb6.c b/server/mdb6.c
+index da7baf6e..ebe01e56 100644
+--- a/server/mdb6.c
++++ b/server/mdb6.c
+@@ -1945,7 +1945,7 @@ create_prefix6(struct ipv6_pool *pool, struct iasubopt **pref,
+ 		}
+ 		new_ds.data = new_ds.buffer->data;
+ 		memcpy(new_ds.buffer->data, ds.data, ds.len);
+-		memcpy(new_ds.buffer->data + ds.len, &tmp, sizeof(tmp));
++		memcpy(&new_ds.buffer->data[0] + ds.len, &tmp, sizeof(tmp));
+ 		data_string_forget(&ds, MDL);
+ 		data_string_copy(&ds, &new_ds, MDL);
+ 		data_string_forget(&new_ds, MDL);
+-- 
+GitLab
+