Compile meminfo for dfly (#315)

* Compile meminfo for dfly

* Update README.me

README.md

@@ -26,7 +26,7 @@ filefd | Exposes file descriptor statistics from `/proc/sys/fs/file-nr`. | Linux
 filesystem | Exposes filesystem statistics, such as disk space used. | FreeBSD, Dragonfly, Linux, OpenBSD
 loadavg | Exposes load average. | Darwin, Dragonfly, FreeBSD, Linux, NetBSD, OpenBSD, Solaris
 mdadm | Exposes statistics about devices in `/proc/mdstat` (does nothing if no `/proc/mdstat` present). | Linux
-meminfo | Exposes memory statistics. | FreeBSD, Linux
+meminfo | Exposes memory statistics. | Dragonfly, FreeBSD, Linux
 netdev | Exposes network interface statistics such as bytes transferred. | Dragonfly, FreeBSD, Linux, OpenBSD
 netstat | Exposes network statistics from `/proc/net/netstat`. This is the same information as `netstat -s`. | Linux
 stat | Exposes various statistics from `/proc/stat`. This includes CPU usage, boot time, forks and interrupts. | Linux

collector/meminfo_bsd.go

@@ -11,7 +11,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// +build freebsd darwin,amd64
+// +build freebsd darwin,amd64 dragonfly
 // +build !nomeminfo
 
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