Explicitly give command line to link an executable

Apparently Make did not have a built-in rule to build “.exe” files on
Windows.
Set files to binary mode
Search for the “.pc” directory when determining the base directory
Support a “.pc/quiltrc” config script; cascade the config scripts

Previously, the “/etc/quilt.quiltrc” configuration script would only be used
if none of the others were used. Also, the help message for the “--quiltrc”
option did not mention overriding the $QUILTRC environment variable.

The three default configuration scripts are still inhibited when setting
$QUILTRC or using “--quiltrc”.
Don't search for patches directory (only for .pc)

git-svn-id: file:///srv/svn/quilt/patches/trunk@851 d14a3a22-75bb-674b-ac17-716f8a15ffcb
Merge branches 'quiltrc', 'win' and 'make' into patches