I am creating a package that depends on OpenSSL on macOS. To use SPM to build the package, I need to pass it some build/linker flags:
swift build -Xlinker -L/usr/local/opt/openssl/lib -Xcc -I/usr/local/opt/openssl/include
The problem is that when I build my xcode project using SPM, I cannot pass the flags. In theory I would think the following would work,
swift package generate-xcodeproj -Xlinker -L/usr/local/opt/openssl/lib -Xcc -I/usr/local/opt/openssl/include
but it doesn't and once Xcode project is generated, to build in it, I need to go into the Settings and update the appropriate paths.
This is obviously ugly and also it wouldn't work for proper CI workflow, which depend on features that are currently only supported by xcode project and not SPM.
I have already tried passing these values when doing a command line xcodebuild like the following, but that also didn't work.
xcodebuild -project MyProj.xcodeproj -scheme MyProjScheme HEADER_SEARCH_PATHS=/usr/local/opt/openssl/include LIBRARY_SEARCH_PATHS=/usr/local/opt/openssl/lib build
Any suggestions?
To create an Xcode project with additional flags, we need to do the following 3 steps:
Step 1 - Obtain the proper mapping between compiler/linker flags and the equivalent xcode settings. In this case,
-Xlinker -L/usr/local/opt/openssl/lib -Xcc -I/usr/local/opt/openssl/include
is equivalent to
HEADER_SEARCH_PATHS=/usr/local/opt/openssl/include
LIBRARY_SEARCH_PATHS=/usr/local/opt/openssl/lib
Step 2 - Create an .xcconfig file. For example,
$ less openssl.xcconfig
HEADER_SEARCH_PATHS = /usr/local/opt/openssl/include
LIBRARY_SEARCH_PATHS = /usr/local/opt/openssl/lib
Step 3 - Use the --xcconfig-overrides flag with generate-xcodeproj to make the project use the config file.
swift package generate-xcodeproj --xcconfig-overrides openssl.xcconfig
Now the Xcode project builds out of the box and xcodebuild can be used without any extra flags.