pthread: Added support for pthread condition variables

This is required for std::condition_variable support

Signed-off-by: Amey Inamdar <amey.inamdar@gmail.com>

components/pthread/test/test_cxx_std_future.cpp

@@ -0,0 +1,31 @@
+#include <iostream>
+#include <future>
+#include <thread>
+#include "unity.h"
+ 
+#if __GTHREADS && __GTHREADS_CXX0X
+TEST_CASE("C++ future", "[std::future]")
+{
+    // future from a packaged_task
+    std::packaged_task<int()> task([]{ return 7; }); // wrap the function
+    std::future<int> f1 = task.get_future();  // get a future
+    std::thread t(std::move(task)); // launch on a thread
+ 
+    // future from an async()
+    std::future<int> f2 = std::async(std::launch::async, []{ return 8; });
+ 
+    // future from a promise
+    std::promise<int> p;
+    std::future<int> f3 = p.get_future();
+    std::thread( [&p]{ p.set_value_at_thread_exit(9); }).detach();
+ 
+    std::cout << "Waiting..." << std::flush;
+    f1.wait();
+    f2.wait();
+    f3.wait();
+    std::cout << "Done!\nResults are: "
+              << f1.get() << ' ' << f2.get() << ' ' << f3.get() << '\n';
+    t.join();
+}
+#endif
+