xcode编译出现这种问题：解决办法
1、检查打开是.xcodeproj还是xcworkspace，应该打开的是xcworkspace。
2、xcode-->preference--->locations--->Derived Data (advanced)--->custom 选中relative to workspace
3、如果前两种都解决不了
Build Settings
PODS ROOT in the build settings:
${SRCROOT}/Pods路径发生错误
参考：http://stackoverflow.com/questions/25564946/library-not-fount-lpods
http://stackoverflow.com/questions/23539147/xcode-ld-library-not-found-for-lpods