KNOWN_BUGS: curl compiled on OSX 10.13 failed to run on OSX 10.10

Closes #2905

docs/KNOWN_BUGS

@@ -47,6 +47,7 @@ problems may have been fixed or changed somewhat since this was written!
  5. Build and portability issues
  5.1 tests not compatible with python3
  5.2 curl-config --libs contains private details
+ 5.3 curl compiled on OSX 10.13 failed to run on OSX 10.10
  5.5 can't handle Unicode arguments in Windows
  5.6 cmake support gaps
  5.7 Visual Studio project gaps
@@ -377,6 +378,10 @@ problems may have been fixed or changed somewhat since this was written!
  run that might be needed only for building libcurl. Further, curl-config
  --cflags suffers from the same effects with CFLAGS/CPPFLAGS.
 
+5.3 curl compiled on OSX 10.13 failed to run on OSX 10.10
+
+ See https://github.com/curl/curl/issues/2905
+
 5.5 can't handle Unicode arguments in Windows
 
  If a URL or filename can't be encoded using the user's current codepage then