Replace calls of htonl()/ntohl() with pg_bswap.h for GSSAPI encryption

The in-core equivalents can make use of built-in functions if the
compiler supports this option, making optimizations possible.  0ba99c84
replaced all existing calls in the code base at this time, but b0b39f72
(GSSAPI encryption) has forgotten to do the switch.

Discussion: https://postgr.es/m/20201014055303.GG3349@paquier.xyz

src/backend/libpq/be-secure-gssapi.c

@@ -209,7 +209,7 @@ be_gssapi_write(Port *port, void *ptr, size_t len)
 		PqGSSSendConsumed += input.length;
 
 		/* 4 network-order bytes of length, then payload */
-		netlen = htonl(output.length);
+		netlen = pg_hton32(output.length);
 		memcpy(PqGSSSendBuffer + PqGSSSendLength, &netlen, sizeof(uint32));
 		PqGSSSendLength += sizeof(uint32);
 
@@ -323,7 +323,7 @@ be_gssapi_read(Port *port, void *ptr, size_t len)
 		}
 
 		/* Decode the packet length and check for overlength packet */
-		input.length = ntohl(*(uint32 *) PqGSSRecvBuffer);
+		input.length = pg_ntoh32(*(uint32 *) PqGSSRecvBuffer);
 
 		if (input.length > PQ_GSS_RECV_BUFFER_SIZE - sizeof(uint32))
 			ereport(FATAL,
@@ -509,7 +509,7 @@ secure_open_gssapi(Port *port)
 		/*
 		 * Get the length for this packet from the length header.
 		 */
-		input.length = ntohl(*(uint32 *) PqGSSRecvBuffer);
+		input.length = pg_ntoh32(*(uint32 *) PqGSSRecvBuffer);
 
 		/* Done with the length, reset our buffer */
 		PqGSSRecvLength = 0;
@@ -567,7 +567,7 @@ secure_open_gssapi(Port *port)
 		 */
 		if (output.length > 0)
 		{
-			uint32		netlen = htonl(output.length);
+			uint32		netlen = pg_hton32(output.length);
 
 			if (output.length > PQ_GSS_SEND_BUFFER_SIZE - sizeof(uint32))
 				ereport(FATAL,

src/interfaces/libpq/fe-secure-gssapi.c

@@ -226,7 +226,7 @@ pg_GSS_write(PGconn *conn, const void *ptr, size_t len)
 		PqGSSSendConsumed += input.length;
 
 		/* 4 network-order bytes of length, then payload */
-		netlen = htonl(output.length);
+		netlen = pg_hton32(output.length);
 		memcpy(PqGSSSendBuffer + PqGSSSendLength, &netlen, sizeof(uint32));
 		PqGSSSendLength += sizeof(uint32);
 
@@ -346,7 +346,7 @@ pg_GSS_read(PGconn *conn, void *ptr, size_t len)
 		}
 
 		/* Decode the packet length and check for overlength packet */
-		input.length = ntohl(*(uint32 *) PqGSSRecvBuffer);
+		input.length = pg_ntoh32(*(uint32 *) PqGSSRecvBuffer);
 
 		if (input.length > PQ_GSS_RECV_BUFFER_SIZE - sizeof(uint32))
 		{
@@ -589,7 +589,7 @@ pqsecure_open_gss(PGconn *conn)
 		 */
 
 		/* Get the length and check for over-length packet */
-		input.length = ntohl(*(uint32 *) PqGSSRecvBuffer);
+		input.length = pg_ntoh32(*(uint32 *) PqGSSRecvBuffer);
 		if (input.length > PQ_GSS_RECV_BUFFER_SIZE - sizeof(uint32))
 		{
 			printfPQExpBuffer(&conn->errorMessage,
@@ -688,7 +688,7 @@ pqsecure_open_gss(PGconn *conn)
 	}
 
 	/* Queue the token for writing */
-	netlen = htonl(output.length);
+	netlen = pg_hton32(output.length);
 
 	memcpy(PqGSSSendBuffer, (char *) &netlen, sizeof(uint32));
 	PqGSSSendLength += sizeof(uint32);