esp8266/mpconfigport.h: Include sys/types.h for POSIX types definitions.

As required for related functions in stream.h.

esp8266/mpconfigport.h

@@ -116,6 +116,8 @@ typedef void *machine_ptr_t; // must be of pointer size
 typedef const void *machine_const_ptr_t; // must be of pointer size
 typedef long mp_off_t;
 typedef uint32_t sys_prot_t; // for modlwip
+// ssize_t, off_t as required by POSIX-signatured functions in stream.h
+#include <sys/types.h>
 
 #define MP_PLAT_PRINT_STRN(str, len) mp_hal_stdout_tx_strn_cooked(str, len)