Enable more warnings treated as errors

Author: wravery

CMakeLists.txt

@@ -6,6 +6,9 @@ cmake_minimum_required(VERSION 3.15)
 # Enable CMAKE_MSVC_RUNTIME_LIBRARY on Windows: https://cmake.org/cmake/help/latest/policy/CMP0091.html
 cmake_policy(SET CMP0091 NEW)
 
+# Do not set default MSVC warning flags: https://cmake.org/cmake/help/latest/policy/CMP0092.html
+cmake_policy(SET CMP0092 NEW)
+
 # Default to the last updated version from version.txt.
 file(TO_CMAKE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake/version.txt" VERSION_FILE)
 file(READ "${VERSION_FILE}" LATEST_VERSION)
@@ -52,6 +55,13 @@ if(VCPKG_TARGET_TRIPLET)
   endif()
 endif()
 
+# Enable more warnings, and treat warnings as errors.
+if(MSVC)
+  add_compile_options(/W4 /WX /permissive-)
+else()
+  add_compile_options(-Wall -Wextra -pedantic -Werror)
+endif()
+
 function(add_bigobj_flag target)
   if(MSVC)
     # MSVC requires the /bigobj flag if the number of sections gets too big.