How to fix error when install Fabric

Installing collected packages: pycrypto, paramiko
Running setup.py install for pycrypto
    warning: GMP library not found; Not building Crypto.PublicKey._fastmath.
    building 'Crypto.Hash.MD2' extension
    gcc-4.2 -fno-strict-aliasing -fno-common -dynamic -fwrapv -Wall -Wstrict-prototypes -DENABLE_DTRACE -arch i386 -arch ppc -arch x86_64 -pipe -std=c99 -O3 -fomit-frame-pointer -Isrc/ -I/System/Library/Frameworks/Python.framework/Versions/2.6/include/python2.6 -c src/MD2.c -o build/temp.macosx-10.6-universal-2.6/src/MD2.o
    /usr/libexec/gcc/powerpc-apple-darwin10/4.2.1/as: assembler (/usr/bin/../local/libexec/as/ppc/as or /usr/bin/../local/libexec/gcc/darwin/ppc/as) for architecture ppc not installed
    Installed assemblers are:
    /usr/bin/../libexec/as/x86_64/as for architecture x86_64
    /usr/bin/../libexec/as/i386/as for architecture i386
    /usr/bin/../libexec/as/arm/as for architecture arm
    src/MD2.c:134: fatal error: error writing to -: Broken pipe
    compilation terminated.
    lipo: can't open input file: /var/tmp//cc2qfvbZ.out (No such file or directory)
    error: command 'gcc-4.2' failed with exit status 1
    Complete output from command /usr/bin/python -c "import setuptools;__file__='/Users/Kelvin/build/pycrypto/setup.py';execfile(__file__)" install --single-version-externally-managed --record /tmp/pip-4O2Z1I-record/install-record.txt:
    running install
    .....

    lipo: can't open input file: /var/tmp//cc1IbrXz.out (No such file or directory)

    error: command 'gcc-4.2' failed with exit status 1

If you got above error when you install the fabric, refer to the following comman:

sudo ARCHFLAGS="-arch i386 -arch x86_64" pip install Fabric

Reason: in Xcode 4, gcc removed the -arch ppc