Fix the case of using STL without pthreads but with mutexes

On non-POSIX targets in STL mode, std::mutex is included from
mutex.h but will probably miss pthreads. Instead, other
implementations might be detected and used in mutex.h.

Therefore, adding ETL_NO_STD_MUTEX as a profile option for ETL.

Further, removing unnecessary includes from queue headers.

include/etl/mutex.h

@@ -40,7 +40,7 @@ SOFTWARE.
 #elif defined(ETL_TARGET_OS_THREADX)
   #include "mutex/mutex_threadx.h"
   #define ETL_HAS_MUTEX 1
-#elif ETL_USING_STL && ETL_USING_CPP11
+#elif ETL_USING_STL && ETL_USING_CPP11 && ETL_USING_STD_MUTEX
   #include "mutex/mutex_std.h"
   #define ETL_HAS_MUTEX 1
 #elif defined(ETL_COMPILER_ARM5) || defined(ETL_COMPILER_ARM6) || defined(ETL_COMPILER_ARM7) || defined(ETL_COMPILER_ARM8)

include/etl/platform.h

@@ -102,6 +102,16 @@ SOFTWARE.
   #define ETL_NOT_USING_STL 0
 #endif
 
+//*************************************
+// Helper macros for ETL_NO_STD_MUTEX.
+#if defined(ETL_NO_STD_MUTEX)
+  #define ETL_USING_STD_MUTEX     0
+  #define ETL_NOT_USING_STD_MUTEX 1
+#else
+  #define ETL_USING_STD_MUTEX     1
+  #define ETL_NOT_USING_STD_MUTEX 0
+#endif
+
 //*************************************
 // Helper macros for ETL_STLPORT.
 #if defined(ETL_STLPORT)

include/etl/queue_lockable.h

@@ -36,7 +36,6 @@ SOFTWARE.
 #include "integral_limits.h"
 #include "memory.h"
 #include "memory_model.h"
-#include "mutex.h"
 #include "parameter_type.h"
 #include "placement_new.h"
 #include "utility.h"

include/etl/queue_spsc_isr.h

@@ -35,7 +35,6 @@ SOFTWARE.
 #include "alignment.h"
 #include "integral_limits.h"
 #include "memory_model.h"
-#include "mutex.h"
 #include "parameter_type.h"
 #include "placement_new.h"
 #include "utility.h"

include/etl/queue_spsc_locked.h

@@ -36,7 +36,6 @@ SOFTWARE.
 #include "integral_limits.h"
 #include "memory.h"
 #include "memory_model.h"
-#include "mutex.h"
 #include "parameter_type.h"
 #include "placement_new.h"
 #include "utility.h"