patch for C++ makefile

[Nuno Santos]

I've been made aware that some posix headers were missing from the M2 
-devel rpm.

I'm attaching a short patch that fixes the problem, if someone could 
apply it I'd appreciate it.

Thanks,
Nuno

Index: lib/common/Makefile.am
===================================================================
--- lib/common/Makefile.am      (revision 574722)
+++ lib/common/Makefile.am      (working copy)
@@ -125,6 +125,7 @@
   $(framing)/Value.h                           \
   $(framing)/amqp_framing.h                    \
   $(framing)/amqp_types.h                      \
+  $(posix_hdr)                                 \
   Exception.h                                  \
   ExceptionHolder.h                            \
   QpidError.h                                  \