Xcode 15 introduced a new linker (see the Xcode 15 release notes). Apparently with this linker it is no longer necessary to explicitly link the C++ standard library runtime. If you do add the -lc++ linker flag, though, then the linker emits the warning above.
Apparently somewhere, somehow, the project seems to pick up the -lc++ flag.
Analysis
The project itself no longer sets the -lc++ linker flag, but it inherits this flag from the generated CocoaPods project. It is currently not clear why CocoaPods sets the -lc++ flag, but in any case the flag can be found in the various generated .xcconfig files. Search for the flag like this:
$ grep -ri -- c++ Pods | grep -- -l | cut -d":" -f1 | sort | uniq
Pods/Target Support Files/Pods-All Targets-Little Go/Pods-All Targets-Little Go.debug.xcconfig
Pods/Target Support Files/Pods-All Targets-Little Go/Pods-All Targets-Little Go.distribute_adhoc.xcconfig
Pods/Target Support Files/Pods-All Targets-Little Go/Pods-All Targets-Little Go.distribute_appstore.xcconfig
Pods/Target Support Files/Pods-All Targets-Little Go/Pods-All Targets-Little Go.release.xcconfig
Pods/Target Support Files/Pods-All Targets-Unit tests/Pods-All Targets-Unit tests.debug.xcconfig
Pods/Target Support Files/Pods-All Targets-Unit tests/Pods-All Targets-Unit tests.distribute_adhoc.xcconfig
Pods/Target Support Files/Pods-All Targets-Unit tests/Pods-All Targets-Unit tests.distribute_appstore.xcconfig
Pods/Target Support Files/Pods-All Targets-Unit tests/Pods-All Targets-Unit tests.release.xcconfig
Example line from one of the files:
OTHER_LDFLAGS = $(inherited) [...] -l"c++" [...]
Status / Workaround
The linker warning is nothing serious and can effectively be ignored.
To get rid of the warning temporarily you can manually edit the .xcconfig files and remove the -l"c++".
A standard build of this project with Xcode 15 generates the following warning:
What does the warning mean?
Xcode 15 introduced a new linker (see the Xcode 15 release notes). Apparently with this linker it is no longer necessary to explicitly link the C++ standard library runtime. If you do add the
-lc++linker flag, though, then the linker emits the warning above.Apparently somewhere, somehow, the project seems to pick up the
-lc++flag.Analysis
The project itself no longer sets the
-lc++linker flag, but it inherits this flag from the generated CocoaPods project. It is currently not clear why CocoaPods sets the-lc++flag, but in any case the flag can be found in the various generated.xcconfigfiles. Search for the flag like this:Example line from one of the files:
Status / Workaround
The linker warning is nothing serious and can effectively be ignored.
To get rid of the warning temporarily you can manually edit the
.xcconfigfiles and remove the-l"c++".