首先，要安装GCC 4.8, 参考前文：Ubuntu 12.04 & 13.04 安装 GCC4.8.1

其中，重点是安装multilib

apt-get install gcc-4.8-multilib  

接着前文premake管理一个solution和多个project的目录树做一些修改：

1.创建四个configuration，分别为Debu64, Release64, Debug32和Release32, 把它们放在solution下面，这样，每个proejct都共享这些设置。

-- A solution contains projects, and defines the available configurations

solution ("solution2")

configurations {"Debug64", "Release64", "Debug32", "Release32"}

location "build"

targetdir "output"

configuration "Debug64"

defines { "DEBUG" }

flags { "Symbols" }

configuration "Release64"

defines { "NDEBUG" }

flags { "Optimize" }

configuration "Debug32"

linkoptions {"-m32"}

defines { "DEBUG -m32" }

flags { "Symbols" }

configuration "Release32"

linkoptions {"-m32"}

defines { "NDEBUG, -m32" }

flags { "Optimize" }

2. 注意上面的32位的配置，添加了linkoptions，并且在defines里面添加了-m32, 这里很别扭。因为-m 在gcc中叫做machine options参数，而premake中没有对应的，只能用defines函数添加。下面这个方式很不好，虽然work.

defines {"DEBUG -m32"}

3. 编译并检查

然后开始运行命令：

/solution2$ premake4 --file=config.lua gmake

Building configurations...

Running action 'gmake'...

Generating build/Makefile...

Generating build/hello1/Makefile...

Generating build/hello2/Makefile...

Done.

进入build目录，开始编译

 cd build/

CHN\shu6889@sloop2:~/work/gitlab/raster/codes/study/premake/solution2/build$ make config=debug32

==== Building hello1 (debug32) ====

Creating ../../output

Creating obj/Debug32

main.cpp

Linking hello1

==== Building hello2 (debug32) ====

Creating obj/Debug32

main.cpp

Linking hello2

现在检查output目录中的两个binary，看看是不是32位。

solution2/build$ cd ../output/

CHN\shu6889@sloop2:~/work/gitlab/raster/codes/study/premake/solution2/output$ file hello1

hello1: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.24, BuildID[sha1]=0x21747ca29b73061ed5ff3d122c8b2318941bce5d, not stripped

CHN\shu6889@sloop2:~/work/gitlab/raster/codes/study/premake/solution2/output$ file hello2

hello2: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), dynamically linked (uses shared libs), for GNU/Linux 2.6.24, BuildID[sha1]=0x975e62f065dc80f22aaa22da30b4f65d4a8b2db8, not stripped

编译成功。

4. 现在用clang试一下，添加环境变量：

export CXX=clang++

export CC=clang

重复第3步，成功。