Error Building devel/cmake

[Amit Sengupta]

Many thanks, Walter for sending me the patch for the devel/cmake Makefile.
Unfortunately it didnt solve the issue for me. I was sure the issue was
with some other port on which cmake depends rather than cmake itself. So I
looked up the supporting ports and built them individually and sure enough
it got stuck on ftp/curl because of the new way of handling the default
version of perl (issue 20150914 in UPDATING) . ftp/curl was using perl5.16
which was conflicting with another version already installed. So anyway to
cut a long story short, I cleared out all the ports in my system  and built
them again with portmaster. devel/cmake also compiled fine and now I have
no problems.