MacOS10.13.6_Xcode9.4.1_iOS11.4.1环境，编译lame静态库, libmp3lame.a，支持真机和模拟器全指令集,bitcode

2018年9月4日 修订

1. lame版本升级至lame3.100

https://sourceforge.net/projects/lame/files/lame/

2. build脚本编译更新, 请仔细阅读文中脚本代码的改动

https://github.com/kewlbear/lame-ios-build

3. 支持bitcode

4. 支持xcode9.4.1

5. 支持模拟器和真机指令集(64位).

编译好的全指令集库下载, fat-lame是all in one, thin-lame是各自指令集的包, 同时包含.h文件.

https://download.csdn.net/download/vieri_ch/10647619

如需自行build, 按照如下步骤进行.

1. http://sourceforge.net/projects/lame/files/lame/ 下载lame的最新版本(3.100)解压到一个文件夹里. 例如lame，

完整路径如下

/Users/maios/Downloads/lame

2.下载build的脚本，https://github.com/kewlbear/lame-ios-build,下载之后得到build-lame.sh, 复制到如下路径.

/Users/maios/Downloads/lame

3. 用bbedit或者ultraedit打开这个脚本，按照注释修改

第8行改为

SOURCE=""

第11行改为

SCRATCH="/Users/maios/Downloads/lame"

4. 打开Terminals, 依次输入如下命令行

cd /Users/maios/Downloads/lame

chmod 755 ./build-lame.sh

sudo sh ./build-lame.sh

输入系统密码, 开始编译

5. 编译完成, 生成fat-lame目录和thin-lame目录，分别存放合并所有指令集的静态库，以及各指令集的静态库.

6. 根据所需，copy lame.h和libmp3lame.a文件到project里，就可以正常使用了。

7. 查看.a文件的指令集。

lipo -info libmp3lame.a

Architectures in the fat file: libmp3lame.a are: armv7 armv7s i386 x86_64 arm64

8. 验证.a文件是否支持bitcode , 依次执行以下命令行

cd /Users/maios/Downloads/lame/thin-lame/arm64/lib/
ar -x libmp3lame.a

解压抽取出lame.o文件

otool -l lame.o | grep bitcode

返回如下结果, 便是表示该.a库支持bitcode

sectname __bitcode

以下是完整的build的脚本，请注意第8行和第11行。

#!/bin/sh

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

ARCHS="arm64 armv7s x86_64 i386 armv7"

# directories
SOURCE=""
FAT="fat-lame"

SCRATCH="/Users/maios/Downloads/lame"
# 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