Why am I getting this “libxml/tree.h file not found” error?

Question

I just installed Xcode version 4.3.1 and I get this error:

libxml / tree.h file not found

I have also installed Xcode 4.2, and

Answer 1

I already had the header search path and frame work but was getting this error. Forcefully quitting xcode and then restarting it worked for me (I was using xcode 7.2)