Fix spuce build

spuce.patch

$ diff -u a/spuce.rb b/spuce.rb
--- a/spuce.rb	2018-08-13 15:19:16.000000000 +0200
+++ b/spuce.rb	2018-08-13 16:33:28.000000000 +0200
@@ -5,16 +5,17 @@
   url "https://github.com/audiofilter/spuce/archive/0.4.3.tar.gz"
   version "0.4.3"
   sha256 "5688e107b57640ba0485790d64eb16bff855f54f6fa5b2fdab568ee91f6dc687"
+
   depends_on "cmake" => :build
+  depends_on "qt5"

   def install
+    qt5 = Formulary.factory 'qt5'
+
     mkdir "build" do
-      system "cmake", "..", "-DBUILD_TESTING=OFF", "-DCMAKE_PREFIX_PATH=/usr/local/opt/qt5", *std_cmake_args
-      system "make", "install" # if this fails, try separate make/make install steps
+      system "cmake", "..", "-DBUILD_TESTING=OFF", "-DCMAKE_PREFIX_PATH=#{qt5.opt_prefix}", *std_cmake_args
+      system "make"
+      system "make", "install"
     end
   end
-
-  test do
-    system "false"
-  end
 end