Added correct namespaces

posix_mutex.h

@@ -3,6 +3,8 @@
 
 #include <pthread.h>
 
+namespace cppcms {
+
 class mutex_lock {
 	pthread_mutex_t &m;
 public:
@@ -24,4 +26,6 @@ public:
 	~rwlock_wrlock() { pthread_rwlock_unlock(&m); };
 };
 
+}
+
 #endif