Clean up gsport-setup a little

We don't do unar picopkgs anymore.  We probably shouldn't even compile
it actually.  The reason why we do is because I don't want to give up on
the idea that a2cloud may run on macOS at some point—but I'm as likely
to just depend on Homebrew for that on the Mac.

Why Homebrew?  Well, I don't like its installation still (same reason I
don't like ours.  Running a command off a website is unwise.  And of
course people do stuff like that all the time, but Homebrew encourages
it and shouldn't!  So again, why Homebrew?

With fink, you build everything from source, but you inherit the Debian
library dependency hell nonetheless. MacPorts solves the dependency hell
and is very robust, but it's also pretty (subjectively) unfriendly to
new users who don't grok UNIX or even know where to find the M to RTFM.

So we come to brew.  It's pretty lightweight, it feels modern.  It's
distributed so that you need not be part of the in-crowd to work with
it, and its Cellar approach provides makes maintenance easy.  When I
first looked at it, it'd been around for years but it had never really
caught on.  Lots of things were not there or just really outdated and
unloved.  I'm glad to say that's changed and the project feels more
mature now.

setup/gsport-setup

@@ -3,6 +3,39 @@
 
 # to do: replace Spectrum Deluxe (2.5.3) with Spectrum Gold (2.5.4)
 
+# from system_ident
+if [[ -z $ras2_os || -z $ras2_arch ]]; then
+	ras2_os="unknown"
+	if hash lsb_release 2>/dev/null; then
+		if [[ -f /usr/bin/raspi-config ]]; then
+			ras2_os="rpi-$(lsb_release -cs)"
+		else
+			case "$(lsb_release -is)" in
+				Debian)
+					ras2_os="debian-$(lsb_release -cs)"
+					;;
+				*)
+					printf "\nUnknown OS with lsb_release\n"
+					lsb_release -a
+					;;
+			esac
+		fi
+	else
+		uname_s="$(uname -s)"
+		case "$uname_s" in
+			Darwin)
+				ras2_os="$uname_s"
+				;;
+			*)
+				printf "\nUnknown OS with uname -s\n$uname_s\n"
+				;;
+		esac
+	fi
+	ras2_arch="$(uname -m)"
+	export ras2_os ras2_arch
+fi
+
+
 readcharHex () {
 # read one character from file & convert to corresponding hex value
 # arg1: filename
@@ -250,14 +283,6 @@ if ! hash unar 2> /dev/null; then
 		sudo apt-get clean
 	fi
 
-	if ! hash unar 2> /dev/null; then
-		if [[ $downloadBinaries && "$(apt-cache search '^libgnustep-base1.22$')" ]]; then
-			# Dependencies: for unar
-			sudo apt-get -y install libgnustep-base1.22
-			sudo apt-get clean
-			wget -qO- "${a2cBinaryURL}/picopkg/unar-${arch}_${debianName}.tgz" | sudo tar Pzx &> /dev/null
-		fi
-
 		# If all else fails, compile from source.
 
 		if ! hash unar 2> /dev/null; then
@@ -303,7 +328,10 @@ if ! hash nulib2 2> /dev/null; then
 	cd $tempDir
 	if [[ $downloadBinaries ]]; then
 		### ArchiveTools: Install nulib2 binaries
-		wget -qO- "${a2cBinaryURL}/picopkg/nulib2-${arch}_${debianName}.tgz" | sudo tar Pzx
+		wget -q "${a2cBinaryURL}/picopkg/nulib2-${ras2_os}_${ras2_arch}.tgz"
+		if [[ -f "nulib2-${ras2_os}_${ras2_arch}.tgz" ]]; then
+			sudo tar Pzxf "nulib2-${ras2_os}_${ras2_arch}.tgz"
+		fi
 	fi
 
 	if ! hash nulib2 2> /dev/null; then