synscan: set platform specific make target (#72102)

* synscan: set platform specific make target

* synscan: add license

Co-authored-by: Jonathan Chang <me@jonathanchang.org>

Formula/synscan.rb

@@ -3,6 +3,7 @@ class Synscan < Formula
   homepage "http://digit-labs.org/files/tools/synscan/"
   url "http://digit-labs.org/files/tools/synscan/releases/synscan-5.02.tar.gz"
   sha256 "c4e6bbcc6a7a9f1ea66f6d3540e605a79e38080530886a50186eaa848c26591e"
+  license "GPL-2.0-or-later"
   revision 1
 
   bottle do
@@ -22,7 +23,12 @@ class Synscan < Formula
     ENV.append "LIBS", "-L#{Formula["libpcap"].opt_lib} -lpcap"
     system "./configure", "--prefix=#{prefix}",
                           "--with-libpcap=yes"
-    system "make", "macos"
+    on_macos do
+      system "make", "macos"
+    end
+    on_linux do
+      system "make", "linux"
+    end
     system "make", "install"
   end