Merge pull request #371 from hitonanode/cpp20

Update to C++20

Author: hitonanode

.verify-helper/config.toml

@@ -1,7 +1,7 @@
 [[languages.cpp.environments]]
 CXX = "g++"
-CXXFLAGS = ["-std=c++17", "-O2", "-Wall"]
+CXXFLAGS = ["-std=c++20", "-O2", "-Wall"]
 
 [[languages.cpp.environments]]
 CXX = "clang++"
-CXXFLAGS = ["-std=c++17", "-O2", "-Wall"]
+CXXFLAGS = ["-std=c++20", "-O2", "-Wall"]

README.md

@@ -20,8 +20,8 @@
 
 GitHub Actions-based CI is run for the environments below:
 
-- C++17 (GCC): `g++ -std=c++17 -O2 -Wall`
-- C++17 (Clang): `clang++ -std=c++17 -O2 -Wall`
+- C++20 (GCC): `g++ -std=c++20 -O2 -Wall`
+- C++20 (Clang): `clang++ -std=c++20 -O2 -Wall`
 
 ## Installation
 

compile_flags.txt

@@ -0,0 +1,4 @@
+-Wfatal-errors
+-Wall
+-Wextra
+-std=c++20