ha_mroonga: support HA_EXTRA_ABORT_ALTER_COPY for MariaDB >= 10.11.12

## Issue

We got the following error when we built Mroonga with MariaDB.

```
/home/buildbot/storage/mroonga/ha_mroonga.cpp:471:10: error: enumeration value 'HA_EXTRA_ABORT_ALTER_COPY' not handled in switch [-Werror=switch]
```

## Cause

MariaDB 10.11.12 introduced a new `HA_EXTRA_ABORT_ALTER_COPY` operation
for the ha_extra_function enum to handle aborting ALTER TABLE COPY
operations.

## Solution

This change adds support for this new operation.
ref: MariaDB/server@f388222

Author: otegami

CMakeLists.txt

@@ -339,6 +339,7 @@ else()
     mrn_build_flag("-Wall")
     mrn_build_flag("-Wextra")
     mrn_build_flag("-Wsuggest-override")
+    mrn_build_flag("-Wswitch")
     mrn_build_flag("-Wno-unused-parameter")
     mrn_build_flag("-Wno-strict-aliasing")
     mrn_build_flag("-Wno-deprecated")

ha_mroonga.cpp

@@ -657,6 +657,11 @@ static const char* mrn_inspect_extra_function(enum ha_extra_function operation)
   case HA_EXTRA_END_ALTER_COPY:
     inspected = "HA_EXTRA_END_ALTER_COPY";
     break;
+#  ifdef MRN_HAVE_HA_EXTRA_ABORT_ALTER_COPY
+  case HA_EXTRA_ABORT_ALTER_COPY:
+    inspected = "HA_EXTRA_ABORT_ALTER_COPY";
+    break;
+#  endif
 #  ifdef MRN_HAVE_HA_EXTRA_NO_AUTOINC_LOCKING
   case HA_EXTRA_NO_AUTOINC_LOCKING:
     inspected = "HA_EXTRA_NO_AUTOINC_LOCKING";

ha_mroonga.hpp

@@ -97,6 +97,10 @@ extern "C" {
 #  define MRN_HAVE_HA_EXTRA_NO_READ_LOCKING
 #endif
 
+#if (defined(MRN_MARIADB_P) && MYSQL_VERSION_ID >= 101112)
+#  define MRN_HAVE_HA_EXTRA_ABORT_ALTER_COPY
+#endif
+
 #if (defined(MRN_MARIADB_P) &&                                                 \
      ((MYSQL_VERSION_ID >= 100600 && MYSQL_VERSION_ID < 100616) ||             \
       (MYSQL_VERSION_ID >= 101100 && MYSQL_VERSION_ID < 101106)))