Make "DEST" a make.sh construct instead of ad-hoc

Using "DEST" for our build artifacts inside individual bundlescripts was already well-established convention, but this officializes it by having `make.sh` itself set the variable and create the directory, also handling CYGWIN oddities in a single central place (instead of letting them spread outward from `hack/make/binary` like was definitely on their roadmap, whether they knew it or not; sneaky oddities).

Signed-off-by: Andrew "Tianon" Page <admwiggin@gmail.com>

hack/make/binary

@@ -1,16 +1,10 @@
 #!/bin/bash
 set -e
 
-DEST=$1
 BINARY_NAME="docker-$VERSION"
 BINARY_EXTENSION="$(binary_extension)"
 BINARY_FULLNAME="$BINARY_NAME$BINARY_EXTENSION"
 
-# Cygdrive paths don't play well with go build -o.
-if [[ "$(uname -s)" == CYGWIN* ]]; then
-	DEST=$(cygpath -mw $DEST)
-fi
-
 source "${MAKEDIR}/.go-autogen"
 
 echo "Building: $DEST/$BINARY_FULLNAME"