Stop using 'zip -k' to construct the Windows source archive.

It was intended to ensure that people still working with DOS filename
restrictions (or things approximating that, e.g. VFAT) wouldn't have
trouble. Those days are surely long gone, and now zip -k is causing
its own trouble with the new VS2010/VS2012 project files, which
include pairs of filenames that become the same under the zip -k
transformation and hence break the source archive build.

[originally from svn r10155]

mksrcarc.sh

@@ -28,6 +28,6 @@ verbosely() {
     "$@"
 }
 
-verbosely zip -k -l putty-src.zip $text
-verbosely zip -k -l putty-src.zip $bintext
-verbosely zip -k putty-src.zip $bin
+verbosely zip -l putty-src.zip $text
+verbosely zip -l putty-src.zip $bintext
+verbosely zip putty-src.zip $bin