diff --git a/src/include/ndpi_define.h.in b/src/include/ndpi_define.h.in
index 75f41dac2f3..c22d698239d 100644
--- a/src/include/ndpi_define.h.in
+++ b/src/include/ndpi_define.h.in
@@ -394,33 +394,103 @@ static inline u_int64_t get_u_int64_t(const u_int8_t* X, int O)
 
 #if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
 
+#ifndef htobe16
 #define htobe16(x) htons(x)
+#endif
+
+#ifndef htole16
 #define htole16(x) (x)
+#endif
+
+#ifndef be16toh
 #define be16toh(x) ntohs(x)
+#endif
+
+#ifndef le16toh
 #define le16toh(x) (x)
+#endif
+
+#ifndef htobe32
 #define htobe32(x) htonl(x)
+#endif
+
+#ifndef htole32
 #define htole32(x) (x)
+#endif
+
+#ifndef be32toh
 #define be32toh(x) ntohl(x)
+#endif
+
+#ifndef le32toh
 #define le32toh(x) (x)
+#endif
+
+#ifndef htobe64
 #define htobe64(x) ndpi_htonll(x)
+#endif
+
+#ifndef htole64
 #define htole64(x) (x)
+#endif
+
+#ifndef be64toh
 #define be64toh(x) ndpi_ntohll(x)
+#endif
+
+#ifndef le64toh
 #define le64toh(x) (x)
+#endif
 
 #elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
 
+#ifndef htobe16
 #define htobe16(x) (x)
+#endif
+
+#ifndef htole16
 #define htole16(x) __builtin_bswap16(x)
+#endif
+
+#ifndef be16toh
 #define be16toh(x) (x)
+#endif
+
+#ifndef le16toh
 #define le16toh(x) __builtin_bswap16(x)
+#endif
+
+#ifndef htobe32
 #define htobe32(x) (x)
+#endif
+
+#ifndef htole32
 #define htole32(x) __builtin_bswap32(x)
+#endif
+
+#ifndef be32toh
 #define be32toh(x) (x)
+#endif
+
+#ifndef le32toh
 #define le32toh(x) __builtin_bswap32(x)
+#endif
+
+#ifndef htobe64
 #define htobe64(x) (x)
+#endif
+
+#ifndef htole64
 #define htole64(x) __builtin_bswap64(x)
+#endif
+
+#ifndef be64toh
 #define be64toh(x) (x)
+#endif
+
+#ifndef le64toh
 #define le64toh(x) __builtin_bswap64(x)
+#endif
 
 #else
 #error Unexpected __BYTE_ORDER__