Importing CommonCrypto in a Swift framework

ou can actually build a solution that "just works" (no need to copy a module.modulemap and SWIFT_INCLUDE_PATHS settings over to your project, as required by other solutions here), but it does require you to create a dummy framework/module that you'll import into your framework proper. We can also ensure it works regardless of platform (iphoneos, iphonesimulator, or macosx).
Add a new framework target to your project and name it after the system library, e.g., "CommonCrypto". (You can delete the umbrella header, CommonCrypto.h.)

Add a new Configuration Settings File and name it, e.g., "CommonCrypto.xcconfig". (Don't check any of your targets for inclusion.) Populate it with the following:
MODULEMAP_FILE[sdk=iphoneos*]        = \
    $(SRCROOT)/CommonCrypto/iphoneos.modulemap
MODULEMAP_FILE[sdk=iphonesimulator*] = \
    $(SRCROOT)/CommonCrypto/iphonesimulator.modulemap
MODULEMAP_FILE[sdk=macosx*]          = \
    $(SRCROOT)/CommonCrypto/macosx.modulemap

Create the three referenced module map files, above, and populate them with the following:
iphoneos.modulemap
module CommonCrypto [system] {
    header "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS.sdk/usr/include/CommonCrypto/CommonCrypto.h"
    export *
}

iphonesimulator.modulemap
module CommonCrypto [system] {
    header "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator.sdk/usr/include/CommonCrypto/CommonCrypto.h"
    export *
}

macosx.modulemap
module CommonCrypto [system] {
    header "/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.11.sdk/usr/include/CommonCrypto/CommonCrypto.h"
    export *
}


(Replace "Xcode.app" with "Xcode-beta.app" if you're running a beta version. Replace 10.11with your current OS SDK if not running El Capitan.)

On the Info tab of your project settings, under Configurations, set the Debug and Releaseconfigurations of CommonCrypto to CommonCrypto (referencingCommonCrypto.xcconfig).

On your framework target's Build Phases tab, add the CommonCrypto framework to Target Dependencies. Additionally add libcommonCrypto.dylib to the Link Binary With Librariesbuild phase.

Select CommonCrypto.framework in Products and make sure its Target Membership for your wrapper is set to Optional.


You should now be able to build, run and import CommonCrypto in your wrapper framework.
For an example, see how SQLite.swift uses a dummy sqlite3.framework.