mdbx: добавление поддержки MDBX_OUSTED в mdbx_strerror() и C++ API.

src/mdbx.c++

@@ -339,7 +339,7 @@ DEFINE_EXCEPTION(transaction_full)
 DEFINE_EXCEPTION(transaction_overlapping)
 DEFINE_EXCEPTION(duplicated_lck_file)
 DEFINE_EXCEPTION(dangling_map_id)
-
+DEFINE_EXCEPTION(transaction_ousted)
 #undef DEFINE_EXCEPTION
 
 __cold const char *error::what() const noexcept {
@@ -428,6 +428,7 @@ __cold void error::throw_exception() const {
     CASE_EXCEPTION(transaction_overlapping, MDBX_TXN_OVERLAPPING);
     CASE_EXCEPTION(duplicated_lck_file, MDBX_DUPLICATED_CLK);
     CASE_EXCEPTION(dangling_map_id, MDBX_DANGLING_DBI);
+    CASE_EXCEPTION(transaction_ousted, MDBX_OUSTED);
 #undef CASE_EXCEPTION
   default:
     if (is_mdbx_error())

src/misc.c

@@ -168,6 +168,9 @@ __cold const char *mdbx_liberr2str(int errnum) {
   case MDBX_DANGLING_DBI:
     return "MDBX_DANGLING_DBI: Some cursors and/or other resources should be"
            " closed before subDb or corresponding DBI-handle could be (re)used";
+  case MDBX_OUSTED:
+    return "MDBX_OUSTED: The parked read transaction was outed for the sake"
+           " of recycling old MVCC snapshots";
   default:
     return nullptr;
   }