MDEV-5120 Test suite test maria-no-logging fails

stat structure (from <sys/stat.h>) is conditionally defined
to have different layout and size depending on the defined macros.
The correct macro is defined in my_config.h, which means it MUST be
included first (or, at least before <features.h> - so, practically,
before including any system headers).

storage/sphinx/snippets_udf.cc

@@ -13,6 +13,7 @@
 // did not, you can find it at http://www.gnu.org/
 //
 
+#include <my_config.h>
 #include <stdio.h>
 #include <string.h>
 #include <assert.h>