Merge pull request #5050 from Arthapz/improve-c23-and-add-c++26

improve c23 and add c++26 flags support

xmake/modules/core/tools/gcc.lua

@@ -235,8 +235,10 @@ function nf_language(self, stdname)
  , gnu11 = "-std=gnu11"
  , c17 = "-std=c17"
  , gnu17 = "-std=gnu17"
- , clatest = {"-std=c2x", "-std=c17", "-std=c11", "-std=c99", "-std=c89", "-ansi"}
- , gnulatest = {"-std=c2x", "-std=gnu17", "-std=gnu11", "-std=gnu99", "-std=gnu89", "-ansi"}
+ , c23 = {"-std=c23", "-std=c2x"}
+ , gnu23 = {"-std=gnu23", "-std=gnu2x"}
+ , clatest = {"-std=c23", "-std=c2x", "-std=c17", "-std=c11", "-std=c99", "-std=c89", "-ansi"}
+ , gnulatest = {"-std=gnu23", "-std=gnu2x", "-std=gnu17", "-std=gnu11", "-std=gnu99", "-std=gnu89", "-ansi"}
  }
  end
 
@@ -263,8 +265,12 @@ function nf_language(self, stdname)
  , gnuxx23 = {"-std=gnu++23", "-std=c++2b"}
  , cxx2b = "-std=c++2b"
  , gnuxx2b = "-std=gnu++2b"
- , cxxlatest = {"-std=c++23", "-std=c++2b", "-std=c++20", "-std=c++2a", "-std=c++17", "-std=c++14", "-std=c++11", "-std=c++1z", "-std=c++98"}
- , gnuxxlatest = {"-std=gnu++23", "-std=gnu++2b", "-std=gnu++20", "-std=gnu++2a", "-std=gnu++17", "-std=gnu++14", "-std=gnu++11", "-std=c++1z", "-std=gnu++98"}
+ , cxx2c = "-std=c++2c"
+ , gnuxx2c = "-std=gnu++2c"
+ , cxx26 = {"-std=c++26", "-std=c++2c"}
+ , gnuxx26 = {"-std=gnu++26", "-std=gnu++2c"}
+ , cxxlatest = {"-std=c++26", "-std=c++2c", "-std=c++23", "-std=c++2b", "-std=c++20", "-std=c++2a", "-std=c++17", "-std=c++14", "-std=c++11", "-std=c++1z", "-std=c++98"}
+ , gnuxxlatest = {"-std=gnu++26", "-std=gnu++2c", "-std=gnu++23", "-std=gnu++2", "-std=gnu++20", "-std=gnu++2a", "-std=gnu++17", "-std=gnu++14", "-std=gnu++11", "-std=c++1z", "-std=gnu++98"}
  }
  local cxxmaps2 = {}
  for k, v in pairs(_g.cxxmaps) do