define __nonnull

src/include/compiler.h

  */
 #define __const __attribute__ (( const ))
 
+/**
+ * Declare a function's pointer parameters as non-null - i.e. force
+ * compiler to check pointers at compile time and enable possible
+ * optimizations based on that fact
+ */
+#define __nonnull __attribute__ (( nonnull ))
+
 /**
  * Declare a function as used.
  *