The PAM standard allows for messages of any length to be returned
to the client. We were discarding all messages of length greater
than 255. This patch dynamically allocates the message buffers so
we can pass the complete message.

This resolves https://fedorahosted.org/sssd/ticket/432

Upon receiving SIGHUP, the monitor signals all services to reopen their
debug logs. It is also possible to signal individual services to reopen
their particular files.

Fixes: #332

It was broken when the default was changed, making it impossible to silence
from the config file.

Make the counter optional so that alignment safe macros can be used also where
there is no counter to update.
Change arguments names so that they are not deceiving (ptr normlly identify a
pointer)
Turn the memcpy substitute into an inline function so that passing a pointer to
rp and checking for it doesn't make the compiler spit lots of warnings.

Also update BUILD.txt