ShellOut make error?

I was trying to make Publish, and it seems to stop at ShellOut:
```swift build -c release
Fetching https://github.com/johnsundell/plot.git
Fetching https://github.com/johnsundell/shellout.git
Fetching https://github.com/johnsundell/codextended.git
Fetching https://github.com/johnsundell/sweep.git
Fetching https://github.com/johnsundell/ink.git
Fetching https://github.com/johnsundell/files.git
https://github.com/johnsundell/shellout.git @ 2.3.0: error: manifest parse error(s):
:29:9: note: in file included from :29:
#import "string.h"
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/usr/include/string.h:180:10: note: in file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/usr/include/string.h:180:
#include "strings.h"
^
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/usr/include/strings.h:92:10: note: in file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.15.sdk/usr/include/strings.h:92:
#include
^
/usr/local/include/string.h:25:10: error: 'plist/Node.h' file not found
#include
^
:0: error: could not build Objective-C module 'Darwin'
make: *** [install] Error 1
```

Is is a ShellOut problem, or a Publish problem?