Tiny fixes to help MSVC and Clang get closer to building

I haven't been able to get far yet in diagnosing the UFCS perf issue, but in the meantime here are a couple of small tweaks that help MSVC and Clang build this branch...

Author: hsutter

include/cpp2regex.h

@@ -211,7 +211,7 @@ template<typename Error_out> class regex_parser;
 #include <set>
 
 template<typename matcher_wrapper, typename Iter, typename CharT>
-using matcher_wrapper_type = typename matcher_wrapper::wrap<Iter, CharT>;
+using matcher_wrapper_type = typename matcher_wrapper::template wrap<Iter, CharT>;
 
 #line 19 "regex.h2"
 namespace cpp2 {
@@ -1362,7 +1362,7 @@ template<typename CharT, typename matcher_wrapper> class regular_expression {
 #line 2368 "regex.h2"
     public: template<typename Iter> using matcher = matcher_wrapper_type<matcher_wrapper,Iter,CharT>;// TODO: Remove when nested types are allowed: https://github.com/hsutter/cppfront/issues/727
     public: template<typename Iter> using context = matcher<Iter>::context;
-    
+
     // TODO: Named multiple return has problems with templates.
     public: template<typename Iter> class search_return {
         public: bool matched; 
@@ -2228,8 +2228,8 @@ template<typename Func> [[nodiscard]] auto make_on_return(Func const& func) -> a
         auto is_negative {false}; 
         auto is_reset {false}; 
 
-        auto add {0}; 
-        auto remove {0}; 
+        // add    := 0;
+        // remove := 0;
 
         auto apply {[&, _1 = (&is_negative), _2 = (&parser_modifiers)](cpp2::impl::in<expression_flags> flag) mutable -> void{
             if (*cpp2::impl::assert_not_null(_1)) {

source/regex.h2

@@ -14,7 +14,7 @@
 #include <set>
 
 template<typename matcher_wrapper, typename Iter, typename CharT>
-using matcher_wrapper_type = typename matcher_wrapper::wrap<Iter, CharT>;
+using matcher_wrapper_type = typename matcher_wrapper::template wrap<Iter, CharT>;
 
 cpp2: namespace = {
 
@@ -696,8 +696,8 @@ parse_context: type = {
         is_negative := false;
         is_reset    := false;
 
-        add    := 0;
-        remove := 0;
+        // add    := 0;
+        // remove := 0;
 
         apply := :(flag: expression_flags) = {
             if is_negative&$* {