Add casts to avoid some compiler warnings

if the compiler is not able to detect the cast if safe.

m-dict.h

@@ -1846,7 +1846,7 @@ typedef enum {
     DICTI_OA_CONTRACT(dict);						\
     size_t size;							\
     /* Get the size which will allow to fit this capacity */		\
-    size = m_core_roundpow2 (capacity * (1.0 / coeff_up));		\
+    size = m_core_roundpow2 ((uint64_t) (capacity * (1.0 / coeff_up)));		\
     /* Test for overflow of the computation */                          \
     if (M_UNLIKELY (size < capacity)) {					\
       M_MEMORY_FULL((size_t)-1);					\