Fix issue with clang 4.

m-i-shared.h

@@ -44,7 +44,7 @@
    type: name of the type of the structure (aka. struct test_s) - not used currently.
    NOTE: There can be only one interface of this kind in a type! */
 #define ISHARED_PTR_INTERFACE(name, type)       \
-  int M_C(name, _cpt)
+  atomic_int M_C(name, _cpt)
 
 /* Define the intrusive shared pointer type and its static inline functions.
    USAGE: ISHARED_PTR_DEF(name[, oplist]) */

m-shared.h

@@ -63,7 +63,7 @@
 #define SHAREDI_PTR_DEF2(name, type, oplist)                            \
   typedef struct M_C3(shared_, name, _s){				\
     type *data;	/* Pointer to the data */                               \
-    int   cpt;  /* Counter of how many points to the data */            \
+    atomic_int   cpt;  /* Counter of how many points to the data */     \
     bool  combineAlloc; /* Does the data and the ptr share the slot? */ \
   } *M_C3(shared_, name, _t)[1];					\
 									\