Kernel/LibC: Add basic support for pthread_{create,exit}

userspace/tests/test-pthread/main.cpp

@@ -0,0 +1,28 @@
+#include <stdio.h>
+#include <pthread.h>
+#include <unistd.h>
+
+void* thread_func(void*)
+{
+	printf("hello from thread\n");
+	return nullptr;
+}
+
+int main(int argc, char** argv)
+{
+	pthread_t tid;
+
+	printf("creating thread\n");
+
+	if (pthread_create(&tid, nullptr, &thread_func, nullptr) == -1)
+	{
+		perror("pthread_create");
+		return 1;
+	}
+
+	sleep(1);
+
+	printf("exiting\n");
+
+	return 0;
+}