dist.sh: cross-platform mktemp usage

see nsqio#718 (comment)

Author: soar

dist.sh

@@ -30,7 +30,7 @@ echo "... running tests"
 
 for os in linux darwin freebsd windows; do
     echo "... building v$version for $os/$arch"
-    BUILD=$(mktemp -d -t nsq)
+    BUILD=$(mktemp -d ${TMPDIR:-/tmp}/nsq-XXXXX)
     TARGET="nsq-$version.$os-$arch.$goversion"
     GOOS=$os GOARCH=$arch CGO_ENABLED=0 \
         make DESTDIR=$BUILD PREFIX=/$TARGET GOFLAGS="$GOFLAGS" install