Enhance config script to allow selecting SDL1 or 2 backends

sc2/build/unix/build.config

@@ -27,7 +27,7 @@ uqm_requirements()
 
 
 	# Libraries always used
-	use_library SDL 1.2.8 || exit 1
+	have_library SDL 1.2.8 || have_library SDL2 || exit 1
 	use_library libpng || exit 1
 
 	case "$HOST_SYSTEM" in
@@ -194,25 +194,40 @@ uqm_prepare_config()
 	esac
 	
 
-	CHOICE_graphics_OPTIONS="pure opengl"
-	CHOICE_graphics_TITLE="OpenGL graphics support"
-	CHOICE_graphics_OPTION_pure_TITLE="Don't include OpenGL graphics support"
+	CHOICE_graphics_OPTIONS="pure opengl sdl2"
+	CHOICE_graphics_TITLE="Graphics Engine"
+	CHOICE_graphics_OPTION_pure_TITLE="SDL1 without OpenGL graphics support"
 	CHOICE_graphics_OPTION_pure_ACTION='graphics_pure_action'
 	graphics_pure_action() {
-		CFLAGS="$CFLAGS -DGFXMODULE_SDL"
+		CFLAGS="$CFLAGS -DGFXMODULE_SDL -DSDL_DIR=SDL"
 		GFXMODULE=sdl
 		HAVE_OPENGL=0
+		use_library SDL 1.2.8
 	}
-	CHOICE_graphics_OPTION_opengl_TITLE="Include OpenGL graphics support"
+	CHOICE_graphics_OPTION_opengl_TITLE="SDL1 with OpenGL graphics support"
 	CHOICE_graphics_OPTION_opengl_ACTION='graphics_opengl_action'
 	CHOICE_graphics_OPTION_opengl_PRECOND="have_library opengl"
 	graphics_opengl_action() {
-		CFLAGS="$CFLAGS -DGFXMODULE_SDL -DHAVE_OPENGL"
+		CFLAGS="$CFLAGS -DGFXMODULE_SDL -DHAVE_OPENGL -DSDL_DIR=SDL"
 		GFXMODULE=sdl
 		HAVE_OPENGL=1
-		use_library opengl
+		use_library SDL 1.2.8 && use_library opengl
 	}
+	CHOICE_graphics_OPTION_sdl2_TITLE="SDL2 with modern graphics support"
+	CHOICE_graphics_OPTION_sdl2_ACTION='graphics_sdl2_action'
+	graphics_sdl2_action() {
+		CFLAGS="$CFLAGS -DGFXMODULE_SDL -DSDL_DIR=SDL2"
+		GFXMODULE=sdl
+		HAVE_OPENGL=0
+		use_library SDL2
+	}
+	# TODO: Once SDL2 has parity to SDL1, make it the default if
+	#       available.
+	# if have_library SDL2; then
+	#	CHOICE_graphics_DEFAULT=sdl2
+	# else
 	CHOICE_graphics_DEFAULT=opengl
+	# fi
 
 	CHOICE_sound_OPTIONS="mixsdl openal"
 	CHOICE_sound_TITLE="Sound backend"

sc2/build/unix/config_proginfo_host

@@ -75,6 +75,21 @@ case "$HOST_SYSTEM" in
 esac
 
 
+### SDL2 ###
+LIB_SDL2_NAME="Simple DirectMedia Layer version 2.x"
+case "$HOST_SYSTEM" in
+	WINSCW|GCCE|ARMV5)
+		LIB_SDL2_DETECT="false"
+		;;
+	*)
+		LIB_SDL2_DETECT="have_command sdl2-config"
+		LIB_SDL2_CFLAGS='$(sdl2-config --cflags)'
+		LIB_SDL2_LDFLAGS='$(sdl2-config --libs)'
+		LIB_SDL2_VERSION='$(sdl2-config --version)'
+		;;
+esac
+
+
 ### libpng ###
 LIB_libpng_NAME="libpng"
 # libpng generally integrates with pkg-config, but that also generally

sc2/src/port.h

@@ -461,16 +461,8 @@ typedef unsigned int wint_t;
 #endif  /* defined (PORT_WANT_ERRNO) */
 
 // Use SDL_INCLUDE to portably include the SDL files from the right location.
-// TODO: Where the SDL and SDL_image headers are located could be detected
-//       from the build script.
+// The SDL_DIR definition is provided by the build configuration.
 #ifdef __APPLE__
-#	define SDL_DIR SDL
-#else
-	// SDL_image.h directly under the include dir.
-#	undef SDL_DIR
-#endif
-
-#ifdef SDL_DIR
 #	define SDL_INCLUDE(file) <SDL_DIR/file>
 #else
 #	define SDL_INCLUDE(file) <file>