消除 Xcode7 中 directory not found for option 'xxxx' 警告
升级Xcode7之后，你会遇到一些警告信息，诸如以下一条：
ld: warning: directory not found for option '-F/Applications/Xcode-beta.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS9.0.sdk/Developer/Library/Frameworks'
这时候，你可以这么解决：
处理步骤如下：
你可以参考下苹果官方的解决方案哦：
https://forums.developer.apple.com/thread/4256
ASK：
After upgrading an existing swift project I am seeing the following warning when it builds the tests:
ld: warning: directory not found for option '-F/Applications/Xcode-beta.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS9.0.sdk/Developer/Library/Frameworks'
That directory does not exist.. should it be looking for SDKs/iPhoneOS9.0.sdk/System/Library/Frameworks?
Is this something that needs fixing within my project files/build settings/etc?
ANSWER：
Found something when comparing a new project vs an older one...
In the old project, the warning was only being produced by the test target of my projects. Under 'Search Paths', I found it was including two items under 'Framework Search Paths':
$(SDKROOT)/Developer/Library/Frameworks
$(inherited)
The new project kept the 'Framework Search Paths' empty.
Deleting those entries in my older project then removed the warning.
Note: I have not exhaustively compared settings, so there may be additional differences.
