Fixed a bug in Thread::create() causing a crash when the heap is full

miosix/_doc/textdoc/Changelog.txt

 Changelog for Miosix np embedded OS
 
+- Fixed a bug in Thread::create() causing a crash when the heap is full.
 - Changed PROGRAM_CMDLINE for stm32vldiscovery from vsprog to stm32flash
 - Unified the CMSIS directories in the various subdirectories of arch into
   one CMSIS, in order to reduce the amount of code duplication and to avoid

miosix/kernel/kernel.cpp

@@ -299,6 +299,7 @@ Thread *Thread::create(void *(*startfunc)(void *), unsigned int stacksize,
     }
     
     Thread *thread=doCreate(startfunc,stacksize,argv,options,false);
+    if(thread==NULL) return NULL;
     
     //Add thread to thread list
     {