diff --git a/Makefile b/Makefile
index 32037764..46285597 100644
--- a/Makefile
+++ b/Makefile
@@ -68,20 +68,20 @@ endif
 RUSTDOC = rustdoc
 
 # Extracts target from rustc.
-TARGET = $(shell rustc --version 2> /dev/null | awk "/host:/ { print \$$2 }")
+TARGET = $(shell rustc --version verbose 2> /dev/null | awk "/host:/ { print \$$2 }")
 # TARGET = x86_64-unknown-linux-gnu
 # TARGET = x86_64-apple-darwin
 
-TARGET_LIB_DIR = target/$(TARGET)/lib/
+TARGET_LIB_DIR = target/deps/
 
 # Ask 'rustc' the file name of the library and use a dummy name if the source has not been created yet.
 # The dummy file name is used to trigger the creation of the source first time.
 # Next time 'rustc' will return the right file name.
 RLIB_FILE = $(shell (rustc --crate-type=rlib --crate-file-name "$(LIB_ENTRY_FILE)" 2> /dev/null) || (echo "dummy.rlib"))
 # You can't have quotes around paths because 'make' doesn't see it exists.
-RLIB = target/$(TARGET)/lib/$(RLIB_FILE)
+RLIB = target/$(RLIB_FILE)
 DYLIB_FILE = $(shell (rustc --crate-type=dylib --crate-file-name "$(LIB_ENTRY_FILE)" 2> /dev/null) || (echo "dummy.dylib"))
-DYLIB = target/$(TARGET)/lib/$(DYLIB_FILE)
+DYLIB = target/$(DYLIB_FILE)
 
 # Use 'VERBOSE=1' to echo all commands, for example 'make help VERBOSE=1'.
 ifdef VERBOSE
@@ -93,7 +93,7 @@ endif
 all: $(DEFAULT)
 
 help:
-	$(Q)echo "--- rust-empty (0.5 007)"
+	$(Q)echo "--- rust-empty (0.6 003)"
 	$(Q)echo "make run               - Runs executable"
 	$(Q)echo "make exe               - Builds main executable"
 	$(Q)echo "make lib               - Both static and dynamic library"
@@ -110,8 +110,8 @@ help:
 	$(Q)echo "make examples          - Builds examples"
 	$(Q)echo "make cargo-lite-exe    - Setup executable package"
 	$(Q)echo "make cargo-lite-lib    - Setup library package"
-	$(Q)echo "make cargo-exe         - EXPERIMENTAL: Setup executable package"
-	$(Q)echo "make cargo-lib         - EXPERIMENTAL: Setup library package"
+	$(Q)echo "make cargo-exe         - Setup executable package"
+	$(Q)echo "make cargo-lib         - Setup library package"
 	$(Q)echo "make rust-ci-lib       - Setup Travis CI Rust library"
 	$(Q)echo "make rust-ci-exe       - Setup Travis CI Rust executable"
 	$(Q)echo "make rusti             - Setup 'rusti.sh' for interactive Rust"
@@ -211,12 +211,12 @@ cargo-exe: $(EXE_ENTRY_FILE)
 	( \
 		name=$${PWD##/*/} ; \
 		readme=$$((test -e README.md && echo -e "readme = \"README.md\"") || ("")) ; \
-		echo -e "[package]\n\nname = \"$$name\"\nversion = \"0.0\"\n$$readme\nauthors = [\"Your Name <your@email.com>\"]\ntags = []\n\n[[bin]]\n\nname = \"$$name\"\npath = \"$(EXE_ENTRY_FILE)\"\n" > Cargo.toml \
+		echo -e "[package]\n\nname = \"$$name\"\nversion = \"0.0.0\"\n$$readme\nauthors = [\"Your Name <your@email.com>\"]\ntags = []\n\n[[bin]]\n\nname = \"$$name\"\npath = \"$(EXE_ENTRY_FILE)\"\n" > Cargo.toml \
 		&& echo "--- Created 'Cargo.toml' for executable" \
 		&& cat Cargo.toml \
 	)
 
-cargo-lib: $(EXE_ENTRY_FILE)
+cargo-lib: $(LIB_ENTRY_FILE)
 	$(Q)( \
 		test -e Cargo.toml \
 		&& echo "--- The file 'Cargo.toml' already exists" \
@@ -225,7 +225,7 @@ cargo-lib: $(EXE_ENTRY_FILE)
 	( \
 		name=$${PWD##/*/} ; \
 		readme=$$((test -e README.md && echo -e "readme = \"README.md\"") || ("")) ; \
-		echo -e "[package]\n\nname = \"$$name\"\nversion = \"0.0\"\n$$readme\nauthors = [\"Your Name <your@email.com>\"]\ntags = []\n\n[[lib]]\n\nname = \"$$name\"\npath = \"$(LIB_ENTRY_FILE)\"\n" > Cargo.toml \
+		echo -e "[package]\n\nname = \"$$name\"\nversion = \"0.0.0\"\n$$readme\nauthors = [\"Your Name <your@email.com>\"]\ntags = []\n\n[[lib]]\n\nname = \"$$name\"\npath = \"$(LIB_ENTRY_FILE)\"\n" > Cargo.toml \
 		&& echo "--- Created 'Cargo.toml' for executable" \
 		&& cat Cargo.toml \
 	)
@@ -255,7 +255,7 @@ rust-ci-exe: $(EXE_ENTRY_FILE)
 	)
 
 doc: $(SOURCE_FILES) | src/
-	$(Q)$(RUSTDOC) $(LIB_ENTRY_FILE) -L "target/$(TARGET)/lib" \
+	$(Q)$(RUSTDOC) $(LIB_ENTRY_FILE) -L "$(TARGET_LIB_DIR)" \
 	&& echo "--- Built documentation"
 
 run: exe
@@ -267,7 +267,7 @@ target-dir: $(TARGET_LIB_DIR)
 exe: bin/main | $(TARGET_LIB_DIR)
 
 bin/main: $(SOURCE_FILES) | bin/ $(EXE_ENTRY_FILE)
-	$(Q)$(COMPILER) --target "$(TARGET)" $(COMPILER_FLAGS) $(EXE_ENTRY_FILE) -o bin/main -L "target/$(TARGET)/lib" \
+	$(Q)$(COMPILER) --target "$(TARGET)" $(COMPILER_FLAGS) $(EXE_ENTRY_FILE) -o bin/main -L "$(TARGET_LIB_DIR)" -L "target" \
 	&& echo "--- Built executable" \
 	&& echo "--- Type 'make run' to run executable"
 
@@ -280,7 +280,7 @@ test-external: bin/test-external
 	&& ./test-external
 
 bin/test-external: $(SOURCE_FILES) | rlib bin/ src/test.rs
-	$(Q)$(COMPILER) --target "$(TARGET)" $(COMPILER_FLAGS) --test src/test.rs -o bin/test-external -L "target/$(TARGET)/lib" \
+	$(Q)$(COMPILER) --target "$(TARGET)" $(COMPILER_FLAGS) --test src/test.rs -o bin/test-external -L "$(TARGET_LIB_DIR)" -L "target" \
 	&& echo "--- Built external test runner"
 
 test-internal: bin/test-internal
@@ -288,7 +288,7 @@ test-internal: bin/test-internal
 	&& ./test-internal
 
 bin/test-internal: $(SOURCE_FILES) | rlib src/ bin/
-	$(Q)$(COMPILER) --target "$(TARGET)" $(COMPILER_FLAGS) --test $(LIB_ENTRY_FILE) -o bin/test-internal -L "target/$(TARGET)/lib" \
+	$(Q)$(COMPILER) --target "$(TARGET)" $(COMPILER_FLAGS) --test $(LIB_ENTRY_FILE) -o bin/test-internal -L "$(TARGET_LIB_DIR)" -L "target" \
 	&& echo "--- Built internal test runner"
 
 bench: bench-internal bench-external
@@ -305,13 +305,13 @@ lib: rlib dylib
 rlib: $(RLIB)
 
 $(RLIB): $(SOURCE_FILES) | $(LIB_ENTRY_FILE) $(TARGET_LIB_DIR)
-	$(Q)$(COMPILER) --target "$(TARGET)" $(COMPILER_FLAGS) --crate-type=rlib $(LIB_ENTRY_FILE) -L "target/$(TARGET)/lib" --out-dir "target/$(TARGET)/lib/" \
+	$(Q)$(COMPILER) --target "$(TARGET)" $(COMPILER_FLAGS) --crate-type=rlib $(LIB_ENTRY_FILE) -L "$(TARGET_LIB_DIR)" --out-dir "target" \
 	&& echo "--- Built rlib"
 
 dylib: $(DYLIB)
 
 $(DYLIB): $(SOURCE_FILES) | $(LIB_ENTRY_FILE) $(TARGET_LIB_DIR)
-	$(Q)$(COMPILER) --target "$(TARGET)" $(COMPILER_FLAGS) --crate-type=dylib $(LIB_ENTRY_FILE) -L "target/$(TARGET)/lib" --out-dir "target/$(TARGET)/lib/" \
+	$(Q)$(COMPILER) --target "$(TARGET)" $(COMPILER_FLAGS) --crate-type=dylib $(LIB_ENTRY_FILE) -L "$(TARGET_LIB_DIR)" --out-dir "target/" \
 	&& echo "--- Built dylib"
 
 bin/:
@@ -350,7 +350,7 @@ git-ignore:
 examples: $(EXAMPLE_FILES)
 
 $(EXAMPLE_FILES): lib examples-dir
-	$(Q)$(COMPILER) --target "$(TARGET)" $(COMPILER_FLAGS) $@ -L "target/$(TARGET)/lib" --out-dir examples/ \
+	$(Q)$(COMPILER) --target "$(TARGET)" $(COMPILER_FLAGS) $@ -L "$(TARGET_LIB_DIR)" -L "target" --out-dir examples/ \
 	&& echo "--- Built '$@' (make $@)"
 
 $(EXE_ENTRY_FILE): | src/
@@ -416,7 +416,7 @@ while true; do
   echo -n "> "
   read line
   TMP="`mktemp r.XXXXXX`"
-  $(COMPILER) - -o $$TMP -L "target/$(TARGET)/lib/" <<EOF
+  $(COMPILER) - -o $$TMP -L "$(TARGET_LIB_DIR)" <<EOF
   #![feature(globs, macro_rules, phase, struct_variant)]
   extern crate arena;
   extern crate collections;
@@ -585,7 +585,7 @@ function contains() {
 i=0
 function build_deps {
     local current=$$(pwd)
-    for symlib in $$(find target/*/lib -type l) ; do
+    for symlib in $$(find $(TARGET_LIB_DIR) -type l) ; do
         cd $$current
         echo $$symlib
         local original_file=$$(readlink $$symlib)
@@ -606,6 +606,7 @@ function build_deps {
 
         # Remember git directory to not build it twice
         git_dir[i]=$$current_git_dir
+        let i+=1
 
         # Visit the symlinks and build the dependencies
         build_deps
@@ -630,11 +631,13 @@ function build_deps {
             && $$MAKE clean \
             && $$MAKE \
         )
-        let i+=1
     done
     cd $$current
 }
 
+# Mark main project as visited to avoid infinite loop.
+git_dir[i]=$$(pwd)
+let i+=1
 if [ "$$1" == "deps" ]; then
     build_deps
 fi
@@ -675,7 +678,7 @@ loc:
 # prints the commit hash with remote branches containing that commit.
 symlink-info:
 	$(Q)	current=$$(pwd) ; \
-	for symlib in $$(find target/*/lib -type l) ; do \
+	for symlib in $$(find $(TARGET_LIB_DIR) -type l) ; do \
 		cd $$current ; \
 		echo $$symlib ; \
 		original_file=$$(readlink $$symlib) ; \
diff --git a/build.sh b/build.sh
new file mode 100755
index 00000000..da9b733c
--- /dev/null
+++ b/build.sh
@@ -0,0 +1,78 @@
+#!/bin/bash
+# written by bvssvni
+# Modify the setting to do conditional compilation.
+# For example "--cfg my_feature"
+SETTINGS=""
+# ================================================
+
+MAKE=make
+if [ "$OS" == "Windows_NT" ]; then
+    MAKE=mingw32-make
+fi
+
+# Checks if an item exists in an array.
+# Copied from http://stackoverflow.com/questions/3685970/check-if-an-array-contains-a-value
+function contains() {
+    local n=$#
+    local value=${!n}
+    for ((i=1;i < $#;i++)) {
+        if [ "${!i}" == "${value}" ]; then
+            echo "y"
+            return 0
+        fi
+    }
+    echo "n"
+    return 1
+}
+
+# This is a counter used to insert dependencies.
+# It is global because we need an array of all the
+# visited dependencies.
+i=0
+function build_deps {
+    local current=$(pwd)
+    for symlib in $(find target/deps/ -type l) ; do
+        cd $current
+        echo $symlib
+        local original_file=$(readlink $symlib)
+        local original_dir=$(dirname $original_file)
+        cd $original_dir
+
+        # Go to the git root directory.
+        local current_git_dir=$(git rev-parse --show-toplevel)
+        echo "--- Parent $current"
+        echo "--- Child $current_git_dir"
+        cd $current_git_dir
+
+        # Skip building if it is already built.
+        if [ $(contains "${git_dir[@]}" $current_git_dir) == "y" ]; then
+            echo "--- Visited $current_git_dir"
+            continue
+        fi
+
+        # Remember git directory to not build it twice
+        git_dir[i]=$current_git_dir
+        let i+=1
+
+        # Visit the symlinks and build the dependencies
+        build_deps
+
+        # First check for a 'build.sh' script with default settings.
+        # Check for additional 'rust-empty.mk' file. # Compile with the settings flags. # If no other options, build with make.
+        ( test -e build.sh && ./build.sh ) || ( test -e rust-empty.mk && $MAKE -f rust-empty.mk clean && $MAKE -f rust-empty.mk ) || ( echo "--- Building $current_git_dir" && $MAKE clean && $MAKE )
+    done
+    cd $current
+}
+
+# Mark main project as visited to avoid infinite loop.
+git_dir[i]=$(pwd)
+let i+=1
+if [ "$1" == "deps" ]; then
+    build_deps
+fi
+
+echo "--- Building $(pwd)"
+( test -e rust-empty.mk && $MAKE -f rust-empty.mk clean && $MAKE -f rust-empty.mk COMPILER_FLAGS+="$SETTINGS" ) || ( $MAKE clean
+    $MAKE COMPILER_FLAGS+="$SETTINGS"
+)
+
diff --git a/src/sdl2_mixer/ffi.rs b/src/sdl2_mixer/ffi.rs
index c6d675fa..dc16a72b 100644
--- a/src/sdl2_mixer/ffi.rs
+++ b/src/sdl2_mixer/ffi.rs
@@ -13,7 +13,7 @@ pub static MIX_INIT_OGG: c_uint = 16;
 pub static MIX_INIT_FLUIDSYNTH: c_uint = 32;
 pub struct Struct_Mix_Chunk {
     pub allocated: c_int,
-    pub abuf: *uint8_t,
+    pub abuf: *const uint8_t,
     pub alen: uint32_t,
     pub volume: uint8_t,
 }
@@ -37,55 +37,55 @@ pub type Struct__Mix_Music = c_void;
 pub type Mix_Music = Struct__Mix_Music;
 pub type Mix_EffectFunc_t =
     ::std::option::Option<extern "C" fn
-                              (arg1: c_int, arg2: *c_void, arg3: c_int,
-                               arg4: *c_void)>;
+                              (arg1: c_int, arg2: *const c_void, arg3: c_int,
+                               arg4: *const c_void)>;
 pub type Mix_EffectDone_t =
-    ::std::option::Option<extern "C" fn(arg1: c_int, arg2: *c_void)>;
+    ::std::option::Option<extern "C" fn(arg1: c_int, arg2: *const c_void)>;
 extern "C" {
-    pub fn Mix_Linked_Version() -> *SDL_version;
+    pub fn Mix_Linked_Version() -> *const SDL_version;
     pub fn Mix_Init(flags: c_int) -> c_int;
     pub fn Mix_Quit();
     pub fn Mix_OpenAudio(frequency: c_int, format: uint16_t, channels: c_int,
                          chunksize: c_int) -> c_int;
     pub fn Mix_AllocateChannels(numchans: c_int) -> c_int;
-    pub fn Mix_QuerySpec(frequency: *c_int, format: *uint16_t,
-                         channels: *c_int) -> c_int;
-    pub fn Mix_LoadWAV_RW(src: *SDL_RWops, freesrc: c_int) ->
-     *Mix_Chunk;
-    pub fn Mix_LoadMUS(file: *c_char) -> *Mix_Music;
-    pub fn Mix_LoadMUS_RW(src: *SDL_RWops, freesrc: c_int) ->
-     *Mix_Music;
-    pub fn Mix_LoadMUSType_RW(src: *SDL_RWops, _type: Mix_MusicType,
-                              freesrc: c_int) -> *Mix_Music;
-    pub fn Mix_QuickLoad_WAV(mem: *uint8_t) -> *Mix_Chunk;
-    pub fn Mix_QuickLoad_RAW(mem: *uint8_t, len: uint32_t) -> *Mix_Chunk;
-    pub fn Mix_FreeChunk(chunk: *Mix_Chunk);
-    pub fn Mix_FreeMusic(music: *Mix_Music);
+    pub fn Mix_QuerySpec(frequency: *const c_int, format: *const uint16_t,
+                         channels: *const c_int) -> c_int;
+    pub fn Mix_LoadWAV_RW(src: *const SDL_RWops, freesrc: c_int) ->
+     *const Mix_Chunk;
+    pub fn Mix_LoadMUS(file: *const c_char) -> *const Mix_Music;
+    pub fn Mix_LoadMUS_RW(src: *const SDL_RWops, freesrc: c_int) ->
+     *const Mix_Music;
+    pub fn Mix_LoadMUSType_RW(src: *const SDL_RWops, _type: Mix_MusicType,
+                              freesrc: c_int) -> *const Mix_Music;
+    pub fn Mix_QuickLoad_WAV(mem: *const uint8_t) -> *const Mix_Chunk;
+    pub fn Mix_QuickLoad_RAW(mem: *const uint8_t, len: uint32_t) -> *const Mix_Chunk;
+    pub fn Mix_FreeChunk(chunk: *const Mix_Chunk);
+    pub fn Mix_FreeMusic(music: *const Mix_Music);
     pub fn Mix_GetNumChunkDecoders() -> c_int;
-    pub fn Mix_GetChunkDecoder(index: c_int) -> *c_char;
+    pub fn Mix_GetChunkDecoder(index: c_int) -> *const c_char;
     pub fn Mix_GetNumMusicDecoders() -> c_int;
-    pub fn Mix_GetMusicDecoder(index: c_int) -> *c_char;
-    pub fn Mix_GetMusicType(music: *Mix_Music) -> Mix_MusicType;
+    pub fn Mix_GetMusicDecoder(index: c_int) -> *const c_char;
+    pub fn Mix_GetMusicType(music: *const Mix_Music) -> Mix_MusicType;
     pub fn Mix_SetPostMix(mix_func:
                               ::std::option::Option<extern "C" fn
-                                                        (arg1: *c_void,
-                                                         arg2: *uint8_t,
+                                                        (arg1: *const c_void,
+                                                         arg2: *const uint8_t,
                                                          arg3: c_int)>,
-                          arg: *c_void);
+                          arg: *const c_void);
     pub fn Mix_HookMusic(mix_func:
                              ::std::option::Option<extern "C" fn
-                                                       (arg1: *c_void,
-                                                        arg2: *uint8_t,
+                                                       (arg1: *const c_void,
+                                                        arg2: *const uint8_t,
                                                         arg3: c_int)>,
-                         arg: *c_void);
+                         arg: *const c_void);
     pub fn Mix_HookMusicFinished(music_finished:
                                      ::std::option::Option<extern "C" fn()>);
-    pub fn Mix_GetMusicHookData() -> *c_void;
+    pub fn Mix_GetMusicHookData() -> *const c_void;
     pub fn Mix_ChannelFinished(channel_finished:
                                    ::std::option::Option<extern "C" fn
                                                              (arg1: c_int)>);
     pub fn Mix_RegisterEffect(chan: c_int, f: Mix_EffectFunc_t,
-                              d: Mix_EffectDone_t, arg: *c_void) -> c_int;
+                              d: Mix_EffectDone_t, arg: *const c_void) -> c_int;
     pub fn Mix_UnregisterEffect(channel: c_int, f: Mix_EffectFunc_t) -> c_int;
     pub fn Mix_UnregisterAllEffects(channel: c_int) -> c_int;
     pub fn Mix_SetPanning(channel: c_int, left: uint8_t, right: uint8_t) -> c_int;
@@ -100,18 +100,18 @@ extern "C" {
     pub fn Mix_GroupCount(tag: c_int) -> c_int;
     pub fn Mix_GroupOldest(tag: c_int) -> c_int;
     pub fn Mix_GroupNewer(tag: c_int) -> c_int;
-    pub fn Mix_PlayChannelTimed(channel: c_int, chunk: *Mix_Chunk,
+    pub fn Mix_PlayChannelTimed(channel: c_int, chunk: *const Mix_Chunk,
                                 loops: c_int, ticks: c_int) -> c_int;
-    pub fn Mix_PlayMusic(music: *Mix_Music, loops: c_int) -> c_int;
-    pub fn Mix_FadeInMusic(music: *Mix_Music, loops: c_int, ms: c_int) ->
+    pub fn Mix_PlayMusic(music: *const Mix_Music, loops: c_int) -> c_int;
+    pub fn Mix_FadeInMusic(music: *const Mix_Music, loops: c_int, ms: c_int) ->
      c_int;
-    pub fn Mix_FadeInMusicPos(music: *Mix_Music, loops: c_int, ms: c_int,
+    pub fn Mix_FadeInMusicPos(music: *const Mix_Music, loops: c_int, ms: c_int,
                               position: c_double) -> c_int;
-    pub fn Mix_FadeInChannelTimed(channel: c_int, chunk: *Mix_Chunk,
+    pub fn Mix_FadeInChannelTimed(channel: c_int, chunk: *const Mix_Chunk,
                                   loops: c_int, ms: c_int, ticks: c_int) ->
      c_int;
     pub fn Mix_Volume(channel: c_int, volume: c_int) -> c_int;
-    pub fn Mix_VolumeChunk(chunk: *Mix_Chunk, volume: c_int) -> c_int;
+    pub fn Mix_VolumeChunk(chunk: *const Mix_Chunk, volume: c_int) -> c_int;
     pub fn Mix_VolumeMusic(volume: c_int) -> c_int;
     pub fn Mix_HaltChannel(channel: c_int) -> c_int;
     pub fn Mix_HaltGroup(tag: c_int) -> c_int;
@@ -132,17 +132,17 @@ extern "C" {
     pub fn Mix_SetMusicPosition(position: c_double) -> c_int;
     pub fn Mix_Playing(channel: c_int) -> c_int;
     pub fn Mix_PlayingMusic() -> c_int;
-    pub fn Mix_SetMusicCMD(command: *c_char) -> c_int;
+    pub fn Mix_SetMusicCMD(command: *const c_char) -> c_int;
     pub fn Mix_SetSynchroValue(value: c_int) -> c_int;
     pub fn Mix_GetSynchroValue() -> c_int;
-    pub fn Mix_SetSoundFonts(paths: *c_char) -> c_int;
-    pub fn Mix_GetSoundFonts() -> *c_char;
+    pub fn Mix_SetSoundFonts(paths: *const c_char) -> c_int;
+    pub fn Mix_GetSoundFonts() -> *const c_char;
     pub fn Mix_EachSoundFont(function:
                                  ::std::option::Option<extern "C" fn
-                                                           (arg1: *c_char,
-                                                            arg2: *c_void)
+                                                           (arg1: *const c_char,
+                                                            arg2: *const c_void)
                                                            -> c_int>,
-                             data: *c_void) -> c_int;
-    pub fn Mix_GetChunk(channel: c_int) -> *Mix_Chunk;
+                             data: *const c_void) -> c_int;
+    pub fn Mix_GetChunk(channel: c_int) -> *const Mix_Chunk;
     pub fn Mix_CloseAudio();
 }
diff --git a/src/sdl2_mixer/lib.rs b/src/sdl2_mixer/lib.rs
index 2595847f..aa92862c 100644
--- a/src/sdl2_mixer/lib.rs
+++ b/src/sdl2_mixer/lib.rs
@@ -176,7 +176,7 @@ pub fn get_chunk_decoder(index: int) -> String {
 /// The internal format for an audio chunk.
 #[deriving(PartialEq)] #[allow(raw_pointer_deriving, visible_private_types)]
 pub struct Chunk {
-    pub raw: *ffi::Mix_Chunk,
+    pub raw: *const ffi::Mix_Chunk,
     pub owned: bool
 }
 
@@ -602,7 +602,7 @@ extern "C" fn c_music_finished_hook() {
 /// This is an opaque data type used for Music data.
 #[deriving(PartialEq)] #[allow(raw_pointer_deriving, visible_private_types)]
 pub struct Music {
-    pub raw: *ffi::Mix_Music,
+    pub raw: *const ffi::Mix_Music,
     pub owned: bool,
 }