MSVC support

CMakeLists.txt

@@ -13,7 +13,12 @@ if (NOT DEFINED OPTCON_LOCAL_BUILD)
     FetchContent_MakeAvailable(fmt)
 endif()
 
-add_compile_options(-Wall -Wextra -Wpedantic)
+if (MSVC)
+    # https://learn.microsoft.com/en-us/cpp/build/reference/compiler-option-warning-level?view=msvc-170
+    add_compile_options(/Wall)
+else()
+    add_compile_options(-Wall -Wextra -Wpedantic)
+endif()
 
 add_subdirectory(src)
 add_subdirectory(test)