[bug-sourceinstall] Problem on Interix 3.5

[Kaz Sasayama]

I just happened to know this program this week and tried it on Interix (a POSI
X subsystem in Windows Services for UNIX 3.5).  Compilation went smooth but it
 did not work as it could not know the current working directory.

By tracing its execution, it just failed in getcwd function.  Interix's getcwd
 function cannot be used as 'getcwd (NULL, 0)' and libsrcinst's configure scri
pt builds a replacement version, but it also fails because 'opendir ("..")' fa
ils mysteriously on Interix.

I do not know what is the right fix for this problem, but if I managed sourcei
nstall to use the system's version, it worked fine for me.