cmake: build with -Wdocumentation

test/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.0)
+cmake_minimum_required(VERSION 3.0...3.5)
 project(SDL2_test)
 
 include(CheckCCompilerFlag)
@@ -20,6 +20,32 @@ macro(add_sdl_test_executable TARGET)
     if(AST_NEEDS_RESOURCES)
         list(APPEND SDL_TESTS_NEEDS_ESOURCES ${TARGET})
     endif()
+
+    if(HAVE_GCC_WDOCUMENTATION)
+        target_compile_options(${TARGET} PRIVATE "-Wdocumentation")
+        if(HAVE_GCC_WERROR_DOCUMENTATION)
+            target_compile_options(${TARGET} PRIVATE "-Werror=documentation")
+        endif()
+    endif()
+
+    if(HAVE_GCC_WDOCUMENTATION_UNKNOWN_COMMAND)
+        if(SDL_WERROR)
+            if(HAVE_GCC_WERROR_DOCUMENTATION_UNKNOWN_COMMAND)
+                target_compile_options(${TARGET} PRIVATE "-Werror=documentation-unknown-command")
+            endif()
+        endif()
+        target_compile_options(${TARGET} PRIVATE "-Wdocumentation-unknown-command")
+    endif()
+
+    if(HAVE_GCC_COMMENT_BLOCK_COMMANDS)
+        target_compile_options(${TARGET} PRIVATE "-fcomment-block-commands=threadsafety")
+        target_compile_options(${TARGET} PRIVATE "-fcomment-block-commands=deprecated")
+    else()
+        if(HAVE_CLANG_COMMENT_BLOCK_COMMANDS)
+            target_compile_options(${TARGET} PRIVATE "/clang:-fcomment-block-commands=threadsafety")
+            target_compile_options(${TARGET} PRIVATE "/clang:-fcomment-block-commands=deprecated")
+        endif()
+    endif()
 endmacro()
 
 if(NOT TARGET SDL2::SDL2-static)