Make the CFLAGS more robust.

This patch introduces a shell script to figure out the proper definitions
for the HAVE_CLOCK_ADJTIME and HAVE_ONESTEP_SYNC macros, as well as the
include path. The intent is to "do the right thing" for three different
user scenarios, namely cross compiling, compiling against a custom kernel,
and using a plain old disto kernel.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Convert the hard coded UDS server path into a variable.

This patch changes the macro for the server socket address into a global
variable so that a subsequent patch can provide a way to set the variable.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Introduce a configuration file option for the server's UDS address.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
pmc: add a command line option to select the server's UDS address.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Extend the interface name length to allow any UDS address.

This patch increases the maximum length of an interface name to
accommodate a UNIX domain socket address of 108 bytes. (This value is
hard coded in the glibc headers, and so we cannot use the Linux kernel
header macro, UNIX_PATH_MAX.)

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
pmc: bring the man page more up to date.

Signed-off-by: Richard Cochran <richardcochran@gmail.com>
Merge the configurable UDS server path branch.