In the module nmbd_serverlistdb,

In the routines expire_servers(),

A comparison is being made with a time_t type to see if it is -1.

On a platform where time_t is unsigned, it can never have a negative value.

Some C compilers have an extension where they will promote the -1 to be an
unsigned type with all bits set to make this work, but I would recommend putting
a cast of (time_t) on these comparisons just to make sure that these conversions
work, as from a logical point of view, any comparison of an unsigned value with
a negative number should always be false.

See bug 1888