Thom Brown <thombrown(at)gmail(dot)com> writes:
> In file included from ../../src/include/c.h:851,
> from crypt.c:44:
> ../../src/include/port.h:392: error: expected identifier or '(' before
> '__extension__'
> ../../src/include/port.h:408: error: conflicting types for 'unsetenv'
> /usr/include/stdlib.h:588: note: previous declaration of 'unsetenv' was here
You need to look into why configure failed to detect that your platform
has unsetenv.
regards, tom lane