Solved the problem finally. In my case, i had some dependent project for my static library project. In the dependent project settings, the ARCH was armv7. I made that to 'Standard architectures (armv7, armv7s)' and it compiled successfully. For my static library project, the setting are as follows:
Architectures: Standard architectures (armv7, armv7s)
Base SDK: Latest iOS (iOS 7.0)
Build Active Architectures Only: NO
Supported Platforms: iphonesimulator iphoneos
Valid Architectures: arm64 armv7 armv7s i386