Just a few of the warnings. I just updated to the Xcode available on El-Capitan. I will attach the config.log

In file included from ../examples/ipv6/test-ipv6.cc:23:
In file included from ./ns3/ipv6-address.h:29:
In file included from ./ns3/attribute-helper.h:23:
In file included from ./ns3/attribute.h:26:
./ns3/simple-ref-count.h:84:41: warning: unused parameter 'o' [-Wunused-parameter]
  SimpleRefCount (const SimpleRefCount &o)
                                        ^
./ns3/simple-ref-count.h:90:53: warning: unused parameter 'o' [-Wunused-parameter]
  SimpleRefCount &operator = (const SimpleRefCount &o)
                                                    ^
In file included from ../examples/ipv6/test-ipv6.cc:23:
In file included from ./ns3/ipv6-address.h:29:
In file included from ./ns3/attribute-helper.h:24:
./ns3/attribute-accessor-helper.h:327:28: warning: unused parameter 'object' [-Wunused-parameter]
    virtual bool DoSet (T *object, const V *v) const {
                           ^
./ns3/attribute-accessor-helper.h:327:45: warning: unused parameter 'v' [-Wunused-parameter]
    virtual bool DoSet (T *object, const V *v) const {
                                            ^
./ns3/attribute-accessor-helper.h:387:34: warning: unused parameter 'object' [-Wunused-parameter]
    virtual bool DoGet (const T *object, V *v) const {
                                 ^
./ns3/attribute-accessor-helper.h:387:45: warning: unused parameter 'v' [-Wunused-parameter]
    virtual bool DoGet (const T *object, V *v) const {
                                            ^
../examples/ipv6/test-ipv6.cc:32:11: warning: unused parameter 'argc' [-Wunused-parameter]
main (int argc, char *argv[])
          ^
../examples/ipv6/test-ipv6.cc:32:23: warning: unused parameter 'argv' [-Wunused-parameter]
main (int argc, char *argv[])
                      ^
8 warnings generated.

[ 817/2030] Compiling examples/ipv6/fragmentation-ipv6.cc
In file included from ../examples/ipv6/ping6.cc:33:
In file included from ./ns3/core-module.h:12:
In file included from ./ns3/attribute-accessor-helper.h:23:
In file included from ./ns3/attribute.h:26:
./ns3/simple-ref-count.h:84:41: warning: unused parameter 'o' [-Wunused-parameter]
  SimpleRefCount (const SimpleRefCount &o)
                                        ^
./ns3/simple-ref-count.h:90:53: warning: unused parameter 'o' [-Wunused-parameter]
  SimpleRefCount &operator = (const SimpleRefCount &o)
                                                    ^
In file included from ../examples/ipv6/ping6.cc:33:
In file included from ./ns3/core-module.h:12:
./ns3/attribute-accessor-helper.h:327:28: warning: unused parameter 'object' [-Wunused-parameter]
    virtual bool DoSet (T *object, const V *v) const {
                           ^
./ns3/attribute-accessor-helper.h:327:45: warning: unused parameter 'v' [-Wunused-parameter]
    virtual bool DoSet (T *object, const V *v) const {
                                            ^
./ns3/attribute-accessor-helper.h:387:34: warning: unused parameter 'object' [-Wunused-parameter]
    virtual bool DoGet (const T *object, V *v) const {
                                 ^
./ns3/attribute-accessor-helper.h:387:45: warning: unused parameter 'v' [-Wunused-parameter]
    virtual bool DoGet (const T *object, V *v) const {
                                            ^
In file included from ../examples/ipv6/ping6.cc:34:
In file included from ./ns3/internet-module.h:10:
In file included from ./ns3/arp-cache.h:27:
In file included from ./ns3/packet.h:24:
./ns3/buffer.h:822:55: warning: unused parameter 'dummy' [-Wunused-parameter]
Buffer::Iterator::Iterator (Buffer const*buffer, bool dummy)
                                                      ^
In file included from ../examples/ipv6/ping6.cc:34:
In file included from ./ns3/internet-module.h:77:
./ns3/tcp-congestion-ops.h:108:47: warning: unused parameter 'tcb' [-Wunused-parameter]
  virtual void PktsAcked (Ptr<TcpSocketState> tcb, uint32_t segmentsAcked,
                                              ^
./ns3/tcp-congestion-ops.h:108:61: warning: unused parameter 'segmentsAcked' [-Wunused-parameter]
  virtual void PktsAcked (Ptr<TcpSocketState> tcb, uint32_t segmentsAcked,
                                                            ^
./ns3/tcp-congestion-ops.h:109:39: warning: unused parameter 'rtt' [-Wunused-parameter]
                          const Time& rtt) { }
                                      ^
10 warnings generated.

In file included from ../examples/ipv6/icmpv6-redirect.cc:44:
In file included from ./ns3/core-module.h:12:
In file included from ./ns3/attribute-accessor-helper.h:23:
In file included from ./ns3/attribute.h:26:
./ns3/simple-ref-count.h:84:41: warning: unused parameter 'o' [-Wunused-parameter]
  SimpleRefCount (const SimpleRefCount &o)
                                        ^
./ns3/simple-ref-count.h:90:53: warning: unused parameter 'o' [-Wunused-parameter]
  SimpleRefCount &operator = (const SimpleRefCount &o)
                                                    ^
In file included from ../examples/ipv6/icmpv6-redirect.cc:44:
In file included from ./ns3/core-module.h:12:
./ns3/attribute-accessor-helper.h:327:28: warning: unused parameter 'object' [-Wunused-parameter]
    virtual bool DoSet (T *object, const V *v) const {
                           ^
./ns3/attribute-accessor-helper.h:327:45: warning: unused parameter 'v' [-Wunused-parameter]
    virtual bool DoSet (T *object, const V *v) const {
                                            ^
./ns3/attribute-accessor-helper.h:387:34: warning: unused parameter 'object' [-Wunused-parameter]
    virtual bool DoGet (const T *object, V *v) const {
                                 ^
./ns3/attribute-accessor-helper.h:387:45: warning: unused parameter 'v' [-Wunused-parameter]
    virtual bool DoGet (const T *object, V *v) const {
                                            ^
In file included from ../examples/ipv6/icmpv6-redirect.cc:45:
In file included from ./ns3/internet-module.h:10:
In file included from ./ns3/arp-cache.h:27:
In file included from ./ns3/packet.h:24:
./ns3/buffer.h:822:55: warning: unused parameter 'dummy' [-Wunused-parameter]
Buffer::Iterator::Iterator (Buffer const*buffer, bool dummy)
                                                      ^
In file included from ../examples/ipv6/icmpv6-redirect.cc:45:
In file included from ./ns3/internet-module.h:77:
./ns3/tcp-congestion-ops.h:108:47: warning: unused parameter 'tcb' [-Wunused-parameter]
  virtual void PktsAcked (Ptr<TcpSocketState> tcb, uint32_t segmentsAcked,
                                              ^
./ns3/tcp-congestion-ops.h:108:61: warning: unused parameter 'segmentsAcked' [-Wunused-parameter]
  virtual void PktsAcked (Ptr<TcpSocketState> tcb, uint32_t segmentsAcked,
                                                            ^
./ns3/tcp-congestion-ops.h:109:39: warning: unused parameter 'rtt' [-Wunused-parameter]
                          const Time& rtt) { }
                                      ^
10 warnings generated.

[ 818/2030] Compiling examples/ipv6/fragmentation-ipv6-two-MTU.cc
[ 819/2030] Compiling examples/ipv6/loose-routing-ipv6.cc
In file included from ../examples/ipv6/radvd.cc:35:
In file included from ./ns3/core-module.h:12:
In file included from ./ns3/attribute-accessor-helper.h:23:
In file included from ./ns3/attribute.h:26:
./ns3/simple-ref-count.h:84:41: warning: unused parameter 'o' [-Wunused-parameter]
  SimpleRefCount (const SimpleRefCount &o)
                                        ^
./ns3/simple-ref-count.h:90:53: warning: unused parameter 'o' [-Wunused-parameter]
  SimpleRefCount &operator = (const SimpleRefCount &o)
                                                    ^
In file included from ../examples/ipv6/radvd.cc:35:
In file included from ./ns3/core-module.h:12:
./ns3/attribute-accessor-helper.h:327:28: warning: unused parameter 'object' [-Wunused-parameter]
    virtual bool DoSet (T *object, const V *v) const {
                           ^
./ns3/attribute-accessor-helper.h:327:45: warning: unused parameter 'v' [-Wunused-parameter]
    virtual bool DoSet (T *object, const V *v) const {
                                            ^
./ns3/attribute-accessor-helper.h:387:34: warning: unused parameter 'object' [-Wunused-parameter]
    virtual bool DoGet (const T *object, V *v) const {
                                 ^
./ns3/attribute-accessor-helper.h:387:45: warning: unused parameter 'v' [-Wunused-parameter]
    virtual bool DoGet (const T *object, V *v) const {
                                            ^
In file included from ../examples/ipv6/radvd.cc:36:
In file included from ./ns3/internet-module.h:10:
In file included from ./ns3/arp-cache.h:27:
In file included from ./ns3/packet.h:24:
./ns3/buffer.h:822:55: warning: unused parameter 'dummy' [-Wunused-parameter]
Buffer::Iterator::Iterator (Buffer const*buffer, bool dummy)
                                                      ^
In file included from ../examples/ipv6/radvd.cc:36:
In file included from ./ns3/internet-module.h:77:
./ns3/tcp-congestion-ops.h:108:47: warning: unused parameter 'tcb' [-Wunused-parameter]
  virtual void PktsAcked (Ptr<TcpSocketState> tcb, uint32_t segmentsAcked,
                                              ^
./ns3/tcp-congestion-ops.h:108:61: warning: unused parameter 'segmentsAcked' [-Wunused-parameter]
  virtual void PktsAcked (Ptr<TcpSocketState> tcb, uint32_t segmentsAcked,
                                                            ^
./ns3/tcp-congestion-ops.h:109:39: warning: unused parameter 'rtt' [-Wunused-parameter]
                          const Time& rtt) { }
                                      ^
10 warnings generated.