Merge lp:~kevin.mark/byobu/fix-uptime-osx into lp:byobu

[Kevin Mark]

Fixes the uptime status notification on OS X.

This fixes the uptime status notification on OS X. Previously it would fall back to parsing `uptime` and that would give bad output.

There are a few different ways I could've detected the OS (like what's done in logo) but I think checking for /usr/sbin/sysctl is probably sufficient enough here. I suppose I also could've "fixed" the sed line but I assume it's working somewhere else and I'd have to branch for that anyway.

=== modified file 'usr/lib/byobu/uptime'
--- usr/lib/byobu/uptime	2016-04-07 22:07:52 +0000
+++ usr/lib/byobu/uptime	2016-05-28 14:13:09 +0000
@@ -30,18 +30,25 @@
 	if [ -r /proc/uptime ]; then
 		read u idle < /proc/uptime
 		u=${u%.*}
+	elif [ -x /usr/sbin/sysctl ]; then
+		u=$(/usr/sbin/sysctl -n kern.boottime | cut -f4 -d' ' | cut -d',' -f1)
+		u=$(($(date +%s) - $u))
+	fi
+
+	if [ "$u" ]; then
 		if [ "$u" -gt 86400 ]; then
-			str="$(($u / 86400))d$((($u % 86400) / 3600))h"
+				str="$(($u / 86400))d$((($u % 86400) / 3600))h"
 		elif [ "$u" -gt 3600 ]; then
-			str="$(($u / 3600))h$((($u % 3600) / 60))m"
+				str="$(($u / 3600))h$((($u % 3600) / 60))m"
 		elif [ "$u" -gt 60 ]; then
-			str="$(($u / 60))m"
+				str="$(($u / 60))m"
 		else
-			str="${u}s"
+				str="${u}s"
 		fi
 	else
 		str=$(uptime | sed -e "s/.* up *//" -e "s/ *days, */d/" -e "s/:/h/" -e "s/,.*/m/")
 	fi
+
 	[ -n "$str" ] || return
 	color w b; printf "%s" "${str}"; color --
 }