Allow declarations after statements

The SDL coding standard is C89 plus C++ style comments and mixed code and declarations.

CMakeLists.txt

@@ -570,32 +570,6 @@ if(USE_GCC OR USE_CLANG OR USE_INTELCC OR USE_QCC)
     target_compile_options(sdl-global-options INTERFACE "-fno-strict-aliasing")
   endif()
 
-  # command-line option ‘-Wdeclaration-after-statement’ is valid for C/ObjC but not for C++
-  check_c_compiler_flag(-Wdeclaration-after-statement HAVE_GCC_WDECLARATION_AFTER_STATEMENT)
-  if(HAVE_GCC_WDECLARATION_AFTER_STATEMENT)
-    if(SDL_WERROR)
-      check_c_compiler_flag(-Werror=declaration-after-statement HAVE_GCC_WERROR_DECLARATION_AFTER_STATEMENT)
-      if(HAVE_GCC_WERROR_DECLARATION_AFTER_STATEMENT)
-        if(CMAKE_VERSION VERSION_LESS 3.3)
-          target_compile_options(sdl-global-options INTERFACE "-Werror=declaration-after-statement")
-        else()
-          target_compile_options(sdl-global-options INTERFACE "$<$<COMPILE_LANGUAGE:C>:-Werror=declaration-after-statement>")
-          if(CMAKE_OBJC_COMPILER)
-              target_compile_options(sdl-global-options INTERFACE "$<$<COMPILE_LANGUAGE:OBJC>:-Werror=declaration-after-statement>")
-          endif()
-        endif()
-      endif()
-    endif()
-    if(CMAKE_VERSION VERSION_LESS 3.3)
-      target_compile_options(sdl-global-options INTERFACE "-Wdeclaration-after-statement")
-    else()
-      target_compile_options(sdl-global-options INTERFACE "$<$<COMPILE_LANGUAGE:C>:-Wdeclaration-after-statement>")
-      if(CMAKE_OBJC_COMPILER)
-          target_compile_options(sdl-global-options INTERFACE "$<$<COMPILE_LANGUAGE:OBJC>:-Wdeclaration-after-statement>")
-      endif()
-    endif()
-  endif()
-
   check_c_compiler_flag(-Wdocumentation HAVE_GCC_WDOCUMENTATION)
   if(HAVE_GCC_WDOCUMENTATION)
     if(SDL_WERROR)