[sqlite] loadext bug

[Ken]

Minor bug:

Please add the prototype and defines for the following to sqlite3ext.h

void  (*result_error_toobig)(sqlite3_context*);

#define sqlite3_result_error_toobig    sqlite3_api->result_error_toobig


Without these, externally loadded libs that would like to use error_toobig will 
not load into sqlite.

Thanks,
Ken