disable literals in gcc9.1+

Author: Hana Dusíková

README.md

@@ -53,7 +53,7 @@ More documentation on [pcre.org](https://www.pcre.org/current/doc/html/pcre2synt
 
 #### Template UDL syntax
 
-Compiler must support N3599 extension, as GNU extension in gcc (not in c++2a mode) and clang.
+Compiler must support N3599 extension, as GNU extension in gcc (not in GCC 9.1+) and clang.
 
 ```c++
 constexpr auto match(std::string_view sv) noexcept {
@@ -62,6 +62,8 @@ constexpr auto match(std::string_view sv) noexcept {
 }
 ```
 
+If you need N3599 extension in GCC 9.1+ you can't use -pedantic mode and define macro `CTRE_ENABLE_LITERALS`.
+
 #### C++17 syntax
 
 You can provide pattern as a `constexpr ctll::fixed_string` variable.

include/ctre/literals.hpp

@@ -33,10 +33,6 @@ namespace literals {
 #elif defined __GNUC__
 #if not(__GNUC__ == 9 || __GNUC__ == 10)
 #define CTRE_ENABLE_LITERALS
-#else
-#if !__cpp_nontype_template_parameter_class
-#define CTRE_ENABLE_LITERALS
-#endif
 #endif
 #endif
 

single-header/ctre.hpp

@@ -3636,10 +3636,6 @@ namespace literals {
 #elif defined __GNUC__
 #if not(__GNUC__ == 9 || __GNUC__ == 10)
 #define CTRE_ENABLE_LITERALS
-#else
-#if !__cpp_nontype_template_parameter_class
-#define CTRE_ENABLE_LITERALS
-#endif
 #endif
 #endif