$srcdir gets double slashes
Imported from http://bugzilla.roxen.com/bugzilla/show_bug.cgi?id=2535
Reported by Martin Nilsson, IDA nilsson@pike.ida.liu.se
When configure is ran as ~/Pike/7.3/src/configure it will produce a $srcdir like /home/nilsson//Pike/7.3/src which will cause problems later on. If however configure is ran as /home/nilsson/Pike/7.3/src/configure it will produce the correct $srcdir /home/nilsson/Pike/7.3/src