1. 下載所需要的lame版本
2. 寫自動化指令碼

#!/bin/sh

CONFIGURE_FLAGS="--disable-shared --disable-frontend"

ARCHS="arm64 armv7s x86_64 i386 armv7"

# directories
# SOURCE 解壓後lame的本地地址
SOURCE="修改為自己的lame地址"
FAT="fat-lame"

# SCRATCH 解壓後lame的本地地址
SCRATCH="修改為自己的lame地址"
# must be an absolute path
THIN=`pwd`/"thin-lame"

COMPILE="y"
LIPO="y"

if [ "$*" ]
then
	if [ "$*" = "lipo" ]
	then
		# skip compile
		COMPILE=
	else
		ARCHS="$*"
		if [ $# -eq 1 ]
		then
			# skip lipo
			LIPO=
		fi
	fi
fi

if [ "$COMPILE" ]
then
	CWD=`pwd`
	for ARCH in $ARCHS
	do
		echo "building $ARCH..."
		mkdir -p "$SCRATCH/$ARCH"
		cd "$SCRATCH/$ARCH"

		if [ "$ARCH" = "i386" -o "$ARCH" = "x86_64" ]
		then
		    PLATFORM="iPhoneSimulator"
		    if [ "$ARCH" = "x86_64" ]
		    then
		    	SIMULATOR="-mios-simulator-version-min=7.0"
                        HOST=x86_64-apple-darwin
		    else
		    	SIMULATOR="-mios-simulator-version-min=5.0"
                        HOST=i386-apple-darwin
		    fi
		else
		    PLATFORM="iPhoneOS"
		    SIMULATOR=
                    HOST=arm-apple-darwin
		fi

		XCRUN_SDK=`echo $PLATFORM | tr '[:upper:]' '[:lower:]'`
		CC="xcrun -sdk $XCRUN_SDK clang -arch $ARCH"
		#AS="$CWD/$SOURCE/extras/gas-preprocessor.pl $CC"
		CFLAGS="-arch $ARCH $SIMULATOR"
		if ! xcodebuild -version | grep "Xcode [1-6]\."
		then
			CFLAGS="$CFLAGS -fembed-bitcode"
		fi
		CXXFLAGS="$CFLAGS"
		LDFLAGS="$CFLAGS"

		CC=$CC $CWD/$SOURCE/configure \
		    $CONFIGURE_FLAGS \
                    --host=$HOST \
		    --prefix="$THIN/$ARCH" \
                    CC="$CC" CFLAGS="$CFLAGS" LDFLAGS="$LDFLAGS"

		make -j3 install
		cd $CWD
	done
fi

if [ "$LIPO" ]
then
	echo "building fat binaries..."
	mkdir -p $FAT/lib
	set - $ARCHS
	CWD=`pwd`
	cd $THIN/$1/lib
	for LIB in *.a
	do
		cd $CWD
		lipo -create `find $THIN -name $LIB` -output $FAT/lib/$LIB
	done

	cd $CWD
	cp -rf $THIN/$1/include $FAT
fi
 

3. 編譯檔案

# 進入編譯指令碼的資料夾
cd /xxx/lame
# -rwxr-xr-x 擁有者有讀、寫、執行許可權；而屬組使用者和其他使用者只有讀、執行許可權。
chmod 755 ./build-lame.sh
# 執行指令碼
sudo sh ./build-lame.sh

4. 編譯完成, 生成fat-lame目錄和thin-lame目錄，分別存放合併所有指令集的靜態庫，以及各指令集的靜態庫.
5. 檢視.a檔案的指令集

lipo -info libmp3lame.a

6. 驗證是否支援bitcode

# 解壓抽取lame.o
ar -x libmp3lame.a
# 檢查是否支援bitcode若輸出sectname __bitcode則支援bitcode 
otool -l lame.o | grep bitcode