The GNUstep runtime shipped in Linux distros is GCC-specific and won't
work with clang. You have to build it separately and set the paths
yourself.
In file included from /root/b 05ywf6dg/stringprog@exe/stringprog-unity.m:1:
In file included from /root/b 05ywf6dg/../test cases/objc/2 nsstring/stringprog.m:1:
In file included from /usr/include/GNUstep/Foundation/NSString.h:89:
In file included from /usr/include/GNUstep/Foundation/NSObject.h:30:
In file included from /usr/include/GNUstep/Foundation/NSObjCRuntime.h:213:
/usr/include/GNUstep/GNUstepBase/GSObjCRuntime.h:58:11: fatal error: 'objc/objc.h' file not found
#include <objc/objc.h>
^
On my system, I get the same error and the objc.h path is:
/usr/lib/gcc/x86_64-redhat-linux/6.3.1/include/objc/objc.h