Windows does not provide the glob() functionality used to implement
the /etc/gss/mechs.d/ feature, so we must avoid compiling the
relevant code for windows.  (It would never have been called, anyway.)

Adjust the ccache/Makefile.in rules to not use '-' or '@' in
make variable names that are processed by nmake.

Also in ccache/Makefile.in, remove some latent leading whitespace that
had been previously hidden by the previous rule; this exposed some
flawed dependencies that are now removed.

Windows does not provide sys/socket.h or sys/un.h, so don't try
to include them in cc_kcm.c.

The commit which moved the KKDCP TLS support to a plugin left some
dangling references to checkhost.c byproducts in os/Makefile.in,
which can be safely removed.

Use k5-platform.h in support/json.c instead of a set of system includes;
this lets windows build the static inline helper functions therein.

Make struct k5buf less opaque and get rid of k5buf-int.h.  Make it
easy to initialize a k5buf in an error state so that it can be freed
in a cleanup handler.  Add a function k5_buf_status which returns 0 or
ENOMEM.  Remove k5_buf_data and k5_buf_len.  Rename k5_free_buf to
k5_buf_free.  Adjust all callers to match.

[ghudson@mit.edu: squashed with similar commits]

Include autoconf.h (either directly or via proxy) before system
headers, so that feature test macros defined there can affect the
system namespace.  Where include order was changed, eliminate some
redundant or unnecessary includes.

ticket: 7961

Take advantage of the strerror_r portability wrapper to simplify code
using it.  Remove unused macros related to strerror_r in
ldap_service_stash.c and plugins.c.

ticket: 7961

On systems where strerror_r is not the POSIX version, define it to
k5_strerror_r.  Implement k5_strerror_r in libkrb5support using
strerror_s, strerror, or the GNU strerror_r as appropriate.

ticket: 7961

Remove code to set or reference the length fields of socket addresses
(sa_len/sin_len/sin6_len), since they aren't portable and setting them
is not required.  Remove autoconf tests for those fields which are no
longer used or which were never used.

There is one exception: in localaddr.c, we still neeed to reference
sa_len for the definition of ifreq_size on platforms which have
sa_len.  Leave that behind, along with the autoconf test which defines
SA_LEN.

Use sa_setport and sa_getport in place of existing static helpers or
open-coded switch statements in net-server.c, fake-addrinfo.c, and
svc_tcp.c.

On platforms which support RTLD_NODELETE, use it to load plugin
modules.  While using this flag makes plugins stay in the process map
after libkrb5/libgssapi_krb5 are unloaded, it solves several problems:

1. It prevents plugin modules which link against OpenSSL (PKINIT and
k5tls) from repeatedly initializing instances of libssl or libcrypto,
leaking heap memory each time.  This is only an issue because we
cannot safely uninitialize OpenSSL.

2. It prevents finalization ordering issues from causing a process
crash when unloading libgssapi_krb5 (issue #7135).

3. It makes memory leak tracing with valgrind easier.

ticket: 7947 (new)