IPhone : Lipo in not creating for arm64, armv7

I'm using the lame mp3 encoder to convert the caf formatted file to mp3 format. I downloaded lame and compile and build all architecture like arm64, armv7, armv7s, armv6, i386, i686, x86_64 successfully. I followed this link to create the libraries enter link description here

But im trying to create lipo for armv7, arm64, x86_64 which support to my project. But im getting fatal error.

Here is the error what i'm getting.

fatal error: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/lipo: build/libmp3lame-arm64.a and build/libmp3lame-armv7.a have the same architectures (x86_64) and can't be in the same fat output file.

I tried the all combination which two architectures can create fat file, except single only creating. Please help to me its very urgent, i need it for ios 8.1 and above(please mention which architectures should i put in the fat file for iPhone 4s and above)