mathic: revision bump

Closes #31.

Signed-off-by: Mahrud Sayrafi <3147718+mahrud@users.noreply.github.com>

Formula/mathic.rb

@@ -4,7 +4,7 @@ class Mathic < Formula
   url "https://github.com/Macaulay2/mathic.git", using: :git, branch: "master"
   version "1.0"
   license "LGPL-2.0-or-later"
-  revision 1
+  revision 2
 
   bottle do
     root_url "https://github.com/mahrud/homebrew-tap/releases/download/mathic-1.0_1"
@@ -13,6 +13,12 @@ class Mathic < Formula
     sha256 "150d6cd52bdd8bd3e332e765e0a609414695d160de6b6ed18538958e8747642d" => :x86_64_linux
   end
 
+  unless OS.mac?
+    fails_with gcc: "4"
+    fails_with gcc: "5"
+    depends_on "gcc@9" => :build
+  end
+
   depends_on "cmake" => :build
 
   depends_on "memtailor"