fix some warns from gcc

src/per_curve/eddsa.tmpl.c

@@ -3,10 +3,10 @@
  * @brief EdDSA routines.
  */
 
+#include "word.h"
 #include <decaf/eddsa_$(gf_bits).h>
 #include <decaf/shake.h>
 #include <decaf/sha512.h>
-#include "word.h"
 #include <string.h>
 
 #define API_NAME "$(c_ns)"

src/per_curve/eddsa.tmpl.hxx

@@ -70,7 +70,7 @@ private:
         }
         
         if (SUPPORTS_CONTEXTS) {
-            uint8_t dom[2] = {2, context_.size() };
+            uint8_t dom[2] = {2, (uint8_t)context_.size() };
             update(dom,2);
             update(context_);
         }

src/shake.c

@@ -270,7 +270,7 @@ size_t decaf_sponge_max_output_bytes (
 ) {
     return (s->params->max_out == 0xFF)
         ? SIZE_MAX
-        : ((200-s->params->rate)/2);
+        : (size_t)((200-s->params->rate)/2);
 }
 
 DEFSHAKE(128)