server/modules/filter/Makefile: Fixed problem which prevented cleaning and compiling hintfilter library.

server/core/config.c: Removed unused if..else block from config_get_valint. Changed it also to return value which indicates whether the operation succeed. Added config_get_valbool similar to config_get_valint.
service.c:Added typelib-like struct and array of valid boolean values. Fixed parameter type test in service_set_param_value. Completed boolean type parameter handling.
hintparser.c:Fixed error message for non-maxscale hints.
readwritesplit.c:Added loading of configuration parameters from service to instance and from instance to each new session. Fixed routing condition in get_route_target. Modified get_route_target so that it takes also rw_read_sesvars_from_slaves and rw_write_sesvars_to_all as parameters.
skygw_types.h: added array size counting macro.

query_classifier/query_classifier.h

@@ -25,9 +25,6 @@ Copyright SkySQL Ab
 
 EXTERN_C_BLOCK_BEGIN
 
-bool allow_var_writes_to_slaves = false;
-bool allow_var_reads_from_slaves = false;
-
 /**
  * Query type for skygateway.
  * The meaninful difference is where operation is done and whether master data