[algs] Another try at fixing BEInt constexpr

../src/hb-algs.hh:120:3: error: body of constexpr function ‘constexpr BEInt<Type, 2>::operator Type() const [with Type = short unsigned int]’ not a return-statement

src/hb-algs.hh

@@ -100,6 +100,8 @@ struct BEInt<Type, 2>
   BEInt () = default;
   constexpr BEInt (Type V) : v {uint8_t ((V >>  8) & 0xFF),
 			        uint8_t ((V      ) & 0xFF)} {}
+
+  struct __attribute__((packed)) packed_uint16_t { uint16_t v; };
   constexpr operator Type () const
   {
 #if ((defined(__GNUC__) && __GNUC__ >= 5) || defined(__clang__)) && \
@@ -107,7 +109,6 @@ struct BEInt<Type, 2>
     (__BYTE_ORDER == __LITTLE_ENDIAN || __BYTE_ORDER == __BIG_ENDIAN)
     /* Spoon-feed the compiler a big-endian integer with alignment 1.
      * https://github.com/harfbuzz/harfbuzz/pull/1398 */
-    struct __attribute__((packed)) packed_uint16_t { uint16_t v; };
 #if __BYTE_ORDER == __LITTLE_ENDIAN
     return __builtin_bswap16 (((packed_uint16_t *) this)->v);
 #else /* __BYTE_ORDER == __BIG_ENDIAN */