Add OGRE_EMBED_DEBUG_MODE CMake option

Default is 'auto' which embeds the debug mode when using Make & Ninja,
but doesn't when using XCode & MSVC.
It also supports options "never" and "always"

CMake/ConfigureBuild.cmake

@@ -99,6 +99,18 @@ set(OGRE_SET_USE_SIMD 0)
 set(OGRE_SET_RESTRICT_ALIASING 0)
 set(OGRE_SET_IDSTRING_ALWAYS_READABLE 0)
 set(OGRE_SET_DISABLE_AMD_AGS 0)
+if((OGRE_EMBED_DEBUG_MODE STREQUAL "auto" AND
+		(CMAKE_GENERATOR STREQUAL "Unix Makefiles" OR CMAKE_GENERATOR STREQUAL "Ninja"))
+	OR OGRE_EMBED_DEBUG_MODE STREQUAL "always")
+  set( OGRE_SET_EMBED_DEBUG_MODE 1 )
+  if( OGRE_BUILD_TYPE STREQUAL "debug" )
+	set( OGRE_SET_DEBUG_MODE "OGRE_DEBUG_LEVEL_DEBUG" )
+  else()
+	set( OGRE_SET_DEBUG_MODE "OGRE_DEBUG_LEVEL_RELEASE" )
+  endif()
+else()
+  set( OGRE_SET_EMBED_DEBUG_MODE 0 )
+endif()
 if (OGRE_CONFIG_DOUBLE)
   set(OGRE_SET_DOUBLE 1)
 endif()

CMake/Templates/OgreBuildSettings.h.in

@@ -7,6 +7,10 @@
 #define OGRE_DEBUG_LEVEL_DEBUG @OGRE_DEBUG_LEVEL_DEBUG@
 #define OGRE_DEBUG_LEVEL_RELEASE @OGRE_DEBUG_LEVEL_RELEASE@
 
+#if @OGRE_SET_EMBED_DEBUG_MODE@
+#    define OGRE_DEBUG_MODE @OGRE_SET_DEBUG_MODE@
+#endif
+
 #cmakedefine OGRE_BUILD_RENDERSYSTEM_D3D11
 #cmakedefine OGRE_BUILD_RENDERSYSTEM_GL3PLUS
 #cmakedefine OGRE_BUILD_RENDERSYSTEM_GLES

CMakeLists.txt

@@ -491,6 +491,12 @@ set(OGRE_CONFIG_ALLOCATOR 0 CACHE STRING
 )
 endif ()
 
+set( OGRE_EMBED_DEBUG_MODE auto CACHE STRING
+	"Specify whether OGRE_DEBUG_MODE should be embedded into OgreBuildSettings.h
+	auto - Use 'never' for multi-config generators like MSVC & XCode. Use 'always' for Make & Ninja generators
+	never - Compile headers will determine whether it's a debug build based on macros like _DEBUG, DEBUG & NDEBUG
+	always - OGRE_DEBUG_MODE is embedded into OgreBuildSettings.h, its value is based on CMAKE_BUILD_TYPE"
+)
 set( OGRE_DEBUG_LEVEL_DEBUG 3 CACHE STRING
     "Specify debug level for debug builds:
     0 - None. Disabled. No checks done at all.