MDEV-28106 S3 tries to include thread.h while compiling on Windows

S3 engine and libmarias3 don't compile on Windows

also fixes:
MDEV-28104 Typo in storage/maria/s3_func.c: 'FN_DECVHAR

storage/maria/CMakeLists.txt

@@ -117,7 +117,7 @@ SET(S3_SOURCES s3_func.c
     libmarias3/src/sha256-internal.c libmarias3/src/xml.c
     libmarias3/src/assume_role.c)
 
-IF(NOT PLUGIN_S3 STREQUAL NO)
+IF(NOT PLUGIN_S3 STREQUAL NO AND NOT WIN32)
   FIND_PACKAGE(CURL)
 ENDIF()
 

storage/maria/s3_func.c

@@ -1310,7 +1310,7 @@ my_bool set_database_and_table_from_path(S3_INFO *s3, const char *path)
     if (path[length-1] == FN_LIBCHAR || path[length-1] == '/')
       break;
 #ifdef FN_DEVCHAR
-    if (path[length-1] == FN_DECVHAR)
+    if (path[length-1] == FN_DEVCHAR)
       break;
 #endif
   }