How to add vendor static library in project via podspec

I have to use third-party library in my project. And I want to add it to the project via cocoapods. I create private repository with foo.a, some headers and a podspec. The podspec looks like this:

Pod::Spec.new do |s|
  s.name      = 'FooClient'
  s.version   = '1.0'
  s.summary   = 'Foo client '
  s.source    = { :git => 'https://github.com/Zhorkov023/FooClient' }
  s.license      = 'MIT'

  s.source_files        = "FooClientLibrary/*.h"
  s.ios.vendored_library = 'FooClientLibrary/libFooClient.a'

  s.platform = :ios, '6.0'
  s.requires_arc = true
  s.frameworks = 'Foundation'

end

But I get an error at Linker:

Undefined symbols for architecture armv7:
"_OBJC_CLASS_$_FooSession", referenced from: objc-class-ref in FooClientSingleton.o ld: symbol(s) not found for architecture armv7 clang: error: linker command failed with exit code 1 (use -v to see invocation)

It looks like my project doesn't know about libFooClient.a. Because if I add library by drag and drop everything is ok. I don't understand why.

Please help me.

Solution

I have resolved this issue.

To fix my problem I have to add string $(inherited) in Targets -> Build Settings -> Linking -> Other Linking Flags

Thanks all!