add check for colored ls on openbsd. (retry of #2225)

lib/theme-and-appearance.zsh

@@ -12,8 +12,11 @@ then
     # otherwise, leave ls as is, because NetBSD's ls doesn't support -G
     gls --color -d . &>/dev/null 2>&1 && alias ls='gls --color=tty'
   elif [[ "$(uname -s)" == "OpenBSD" ]]; then
-    # On OpenBSD, test if "colorls" is installed (this one supports colors);
-    # otherwise, leave ls as is, because OpenBSD's ls doesn't support -G
+    # On OpenBSD, "gls" (ls from GNU coreutils) and "colorls" (ls from base, 
+    # with color and multibyte support) are available from ports.  "colorls"  
+    # will be installed on purpose and can't be pulled in by installing 
+    # coreutils, so prefer it to "gls".
+    gls --color -d . &>/dev/null 2>&1 && alias ls='gls --color=tty'
     colorls -G -d . &>/dev/null 2>&1 && alias ls='colorls -G'
   else
     ls --color -d . &>/dev/null 2>&1 && alias ls='ls --color=tty' || alias ls='ls -G'