conditionally include unistd.h to pick up confstr declaration. attempt to squelch warning from GCC 2.95.2 on Solaris - partially addresses bug #232787.
conditionally include unistd.h to pick up confstr declaration. attempt to
squelch warning from GCC 2.95.2 on Solaris - partially addresses bug
#232787.

sk-/python2.7-type-annotator,sk-/python2.7-type-annotator,sk-/python2.7-type-annotator