[Installer] Call the specification hooks per each target definition

Closes #985

lib/cocoapods/installer.rb

@@ -389,7 +389,7 @@ module Pod
           executed = false
           libraries_using_spec(spec).each do |lib|
             lib_representation = library_rep(lib)
-            executed ||= run_spec_pre_install_hook(spec, lib_representation)
+            executed |= run_spec_pre_install_hook(spec, lib_representation)
           end
           UI.message "- #{spec.name}" if executed
         end
@@ -448,7 +448,7 @@ module Pod
           executed = false
           libraries_using_spec(spec).each do |lib|
             lib_representation = library_rep(lib)
-            executed ||= run_spec_post_install_hook(spec, lib_representation)
+            executed |= run_spec_post_install_hook(spec, lib_representation)
           end
           UI.message "- #{spec.name}" if executed
         end

spec/unit/installer_spec.rb

@@ -372,6 +372,27 @@ module Pod
         @installer.send(:run_pre_install_hooks)
       end
 
+      it "calls the hooks in the specs for each target" do
+          library_ios = Library.new(nil)
+          library_osx = Library.new(nil)
+          library_ios.platform = Platform.new(:ios, '6.0')
+          library_osx.platform = Platform.new(:osx, '10.8')
+          library_ios.specs = [@spec]
+          library_osx.specs = [@spec]
+          library_ios.stubs(:name).returns('label')
+          library_osx.stubs(:name).returns('label')
+
+          @installer.stubs(:libraries).returns([library_ios, library_osx])
+
+          @installer.stubs(:installer_rep).returns(stub())
+          @installer.stubs(:library_rep).returns(stub())
+
+          @spec.expects(:pre_install!).twice
+          @spec.expects(:post_install!).twice
+          @installer.send(:run_pre_install_hooks)
+          @installer.send(:run_post_install_hooks)
+      end
+
       it "run_post_install_hooks" do
         installer_rep = stub()
         target_installer_data = stub()