Fix compiler warnings in my_atomic.h

include/atomic/x86-gcc.h:
  Fix a warning about empty while loop body.
include/my_atomic.h:
  Fix a warning about empty while loop body.

include/atomic/x86-gcc.h

@@ -88,7 +88,7 @@
 */
 #define make_atomic_add_body64                                  \
   int64 tmp=*a;                                                 \
-  while (!my_atomic_cas64(a, &tmp, tmp+v));                     \
+  while (!my_atomic_cas64(a, &tmp, tmp+v)) ;                    \
   v=tmp;
 
 /*

include/my_atomic.h

@@ -77,13 +77,13 @@
 #ifndef make_atomic_add_body
 #define make_atomic_add_body(S)                                 \
   int ## S tmp=*a;                                              \
-  while (!my_atomic_cas ## S(a, &tmp, tmp+v));                  \
+  while (!my_atomic_cas ## S(a, &tmp, tmp+v)) ;                 \
   v=tmp;
 #endif
 #ifndef make_atomic_fas_body
 #define make_atomic_fas_body(S)                                 \
   int ## S tmp=*a;                                              \
-  while (!my_atomic_cas ## S(a, &tmp, v));                      \
+  while (!my_atomic_cas ## S(a, &tmp, v)) ;                     \
   v=tmp;
 #endif
 #ifndef make_atomic_load_body