tests: explicitly cast incompatible function pointers

also needed for Darwin CI

tests/casts/src/casts.c

@@ -7,8 +7,8 @@ void cast_stuff(void) {
         const int *cintp = 0;
         char *x1 = (char*) intp;
         int *x2 = (int*) intp;
-        void(*f)(unsigned, int*) = cast_stuff;
-        void(*g)(unsigned, int*) = &cast_stuff;
+        void(*f)(unsigned, int*) = (void(*)(unsigned, int*))cast_stuff;
+        void(*g)(unsigned, int*) = (void(*)(unsigned, int*))&cast_stuff;
         //(union intfloat)1;
         int *x3 = (int*)inta;
         int *x4 = (int*)0;

tests/pointers/src/function_pointers.c

@@ -75,16 +75,16 @@ void entry3(const unsigned sz, int buffer[const])
 
         // Test valid casts between function pointers
         // with additional parameters
-        char_int_to_int_fp p9 = &intval, p10 = p7;
+        char_int_to_int_fp p9 = (char_int_to_int_fp)&intval, p10 = (char_int_to_int_fp)p7;
         buffer[i++] = p9('D', 42);
         buffer[i++] = p10('E', 1337);
 
         // Test K&R style function pointers
-        knr *p11 = 1;
-        knr *p12 = intval;
-        knr *p13 = &intval;
+        knr *p11 = (knr *)1;
+        knr *p12 = (knr *)intval;
+        knr *p13 = (knr *)&intval;
         struct pointer_st s;
-        s.fn = intval;
+        s.fn = (int (*)())intval;
         buffer[i++] = p12('a');
         buffer[i++] = p13('a');
         buffer[i++] = (*(s).fn)(('a'));