The gssapi has some helper functions gssalloc_malloc()/gssalloc_free()
which on windows doesn't call malloc()/free(). Instead these are
wrappers around HeapAlloc() and HeapFree(). To complicate matters
gssapi doesn't export these helper functions, so you're left using
the allocation method of your choice.

See Here:
https://github.com/krb5/krb5/blob/89683d1f135765e91041f3a239af865b11aaf86b/src/lib/gssapi/generic/gssapi_alloc.h

The zmq gssapi implementation is calling malloc and then calling
gss_release_buffer() to free the memory. gss_release_buffer uses
gssalloc_free() to free this buffer which on windows calls HeapFree()
instead of free(). This causes an access violation on windows.

Solution: Phase I - make precompiled.hpp be first file included in every source file

Solution: update to 2016

Solution: Convert to spaces and remove trailing whitespace in these files.

This commit adds ZMTP connection heartbeats described in
http://rfc.zeromq.org/spec:37/ZMTP.

Of course people still "can" distributed the sources under the
LGPLv3. However we provide COPYING.LESSER with additional grants.

Solution: specify these grants in the header of each source file.

Solution: update for 2015

Fixes #1320

Tested on FreeBSD 10.

- also prioritize ZAP metadata over ZMTP metadata in case application
  uses same names.

For exchanging tokens.

E.g., both client and server need to produce and process GSSAPI tokens.