Revert util_expr: sync bison generated source files with server/util_expr_parse.y from r1642154.

Revert r1643900. May someone with a bison version closer to the original one make this change.

util_expr: sync bison generated source files with server/util_expr_parse.y.

update auto-generated code

Update auto-generated source Now using bison 2.7.12

Limit recursion in ap_expr evaluation to avoid unbounded stack usage * evaluate chains of ||, &&, and string concatenation non-recursively * limit other types of recursion to 20 levels * avoid some string copies if concatenating more than 2 strings

Update autogenerated code. Now generated with bison 2.5 instead of 2.4.1

Cleanup effort in prep for GA push: Trim trailing whitespace... no func change

Update auto-generated code

Update auto-generated code

Rename ap_expr's typedef names: ap_expr -> ap_expr_t ap_expr_parse_ctx -> ap_expr_parse_ctx_t ap_expr_eval_ctx -> ap_expr_eval_ctx_t ap_expr_lookup_fn -> ap_expr_lookup_fn_t ap_expr_node_op -> ap_expr_node_op_e

update flex/bison autogenerated code

Fix some Windows build issues

ap_expr related fixes/enhancements: - implement regex backreferences and make them available for setting envvars in SetEnvIfExpr - implement nested function calls in %-syntax: %{func1:%{func2:arg}} - actually implement evaluation of concatenation operator (oops...) - Fix <If ... > treating an internal error as success

Replace ap_expr with a parser derived from mod_ssl's parser. Make mod_ssl use the new parser. Rework ap_expr's public interface and provide hooks for modules to add variables and functions. The Netware and Windows build files still need to be adjusted