Fix hsutter#217 & hsutter#218 ;

Author: prenaux

include/cpp2util.h

@@ -408,7 +408,7 @@ auto assert_in_bounds(auto&& x, auto&& arg CPP2_SOURCE_LOCATION_PARAM_WITH_DEFAU
 #endif
 }
 
-auto Uncaught_exceptions() -> int {
+inline auto Uncaught_exceptions() -> int {
 #ifdef CPP2_NO_EXCEPTIONS
     return 0;
 #else
@@ -888,7 +888,7 @@ auto as( X const& x ) -> auto
     //  Experiment: Recognize the nested `::value_type` pattern for some dynamic library types
     //  like std::optional, and try to prevent accidental narrowing conversions even when
     //  those types themselves don't defend against them
-    if constexpr( requires{ typename C::value_type; } && std::is_convertible_v<X, typename C::value_type> ) {
+    if constexpr( requires{ typename C::value_type; } && requires { std::is_convertible_v<X, typename C::value_type>; } ) {
         if constexpr( is_narrowing_v<typename C::value_type, X>) {
             return nonesuch;
         }