crnlib: do not call sem_destroy on macOS

On macOS, sem_unlink should be used instead of sem_destroy,
what the current code does is to call sem_destroy on every
pthread-compatible system and then call sem_unlink on macOS.

It is expected the only macOS implementation of it and other
functions like sem_init is to do nothing but to exist and
be marked as deprecated so the compiler can print warnings
as the -Wdeprecated-declarations flag is enabled by default.

Because sem_destroy is expected to be a stub on macOS and
we call sem_unlink anyway, the current code works but raises
a “'sem_destroy' is deprecated” warning at build time for
something we don't need and we already have the right
implementation done anyway.

crnlib/crn_threading_pthreads.cpp

@@ -125,8 +125,9 @@ semaphore::semaphore(long initialCount, long maximumCount, const char* pName) {
 }
 
 semaphore::~semaphore() {
+#if !defined(__APPLE__)
   sem_destroy(m_sem);
-#if defined(__APPLE__)
+#else
   sem_unlink(m_name);
 #endif
 }