[sdl] Fix up CMake, compilation on Linux.

CMakeLists.txt

@@ -11,8 +11,8 @@ if(MSVC)
 	set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS}")
 	set (CMAKE_C_FLAGS "${CMAKE_CXX_FLAGS}")
 else()
-	set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wunused-value -Wno-c++11-long-long -Wno-variadic-macros -Wextra -pedantic -Wnonportable-include-path -Wshadow -std=c89")
-	set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wunused-value -Wno-c++11-long-long -Wno-variadic-macros -Wextra -Wnon-virtual-dtor -pedantic -Wnonportable-include-path -Wshadow -std=c++11 -fno-exceptions -fno-rtti")
+	set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wall -Wunused-value -Wno-variadic-macros -Wextra -pedantic -Wshadow -std=c89")
+	set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wunused-value -Wno-variadic-macros -Wextra -Wnon-virtual-dtor -pedantic -Wshadow -std=c++11 -fno-exceptions -fno-rtti")
 
 	if (${SPINE_SANITIZE})
 		set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fsanitize=address -fsanitize=undefined")

spine-sdl/src/spine-sdl-c.c

@@ -30,7 +30,6 @@
 #include "spine-sdl-c.h"
 #include <spine/spine.h>
 #include <spine/extension.h>
-#include <SDL.h>
 
 #define STB_IMAGE_IMPLEMENTATION
 

spine-sdl/src/spine-sdl-c.h

@@ -32,13 +32,12 @@
 
 #include <spine/spine.h>
 
+#include <SDL.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-struct SDL_Renderer;
-struct SDL_Texture;
-struct SDL_Vertex;
 _SP_ARRAY_DECLARE_TYPE(spSdlVertexArray, struct SDL_Vertex)
 
 typedef struct spSkeletonDrawable {

spine-sdl/src/spine-sdl-cpp.h

@@ -31,9 +31,7 @@
 #define SPINE_SDL
 
 #include <spine/spine.h>
-
-struct SDL_Renderer;
-struct SDL_Vertex;
+#include <SDL.h>
 
 namespace spine {
 	class SkeletonDrawable {