Added support to inject "extern C" into runners when generated.

auto/generate_test_runner.rb

@@ -197,9 +197,11 @@ class UnityTestRunnerGenerator
     output.puts("\n/*=======External Functions This Runner Calls=====*/")
     output.puts("extern void #{@options[:setup_name]}(void);")
     output.puts("extern void #{@options[:teardown_name]}(void);")
+    output.puts("\n#ifdef __cplusplus\nextern \"C\"\n{\n#endif") if @options[:externc]
     tests.each do |test|
       output.puts("extern void #{test[:test]}(#{test[:call] || 'void'});")
     end
+    output.puts("#ifdef __cplusplus\n}\n#endif") if @options[:externc]
     output.puts('')
   end
 
@@ -439,6 +441,7 @@ if $0 == __FILE__
           '    *.h                   - header files are added as #includes in runner',
           '  options:',
           '    -cexception           - include cexception support',
+          '    -externc              - add extern "C" for cpp support',
           '    --setup_name=""       - redefine setUp func name to something else',
           '    --teardown_name=""    - redefine tearDown func name to something else',
           '    --main_name=""        - redefine main func name to something else',

docs/UnityHelperScriptsGuide.md

@@ -159,6 +159,12 @@ CMock (see CMock documentation). This generates extra variables required for
 everything to run smoothly. If you provide the same YAML to the generator as
 used in CMock's configuration, you've already configured the generator properly.
 
+
+##### `:externc`
+
+This option should be defined if you are mixing C and CPP and want your test
+runners to automatically include extern "C" support when they are generated.
+
 ##### `:mock_prefix` and `:mock_suffix`
 
 Unity automatically generates calls to Init, Verify and Destroy for every file