Add PB_SYSTEM_HEADER compile time option.

This allows replacing the C99 standard include file names with
a single system-specific file. It should provide all the necessary
system functions (typedefs, memset, memcpy, strlen).

Update issue 62
Status: FixedInGit

pb_decode.c

@@ -14,7 +14,6 @@
 #define NANOPB_INTERNALS
 #include "pb.h"
 #include "pb_decode.h"
-#include <string.h>
 
 typedef bool (*pb_decoder_t)(pb_istream_t *stream, const pb_field_t *field, void *dest) checkreturn;