anchor.diff:  which--not too surprisingly--has greetings as its main purpose. 
   
   [source,c]
  -.`foo.h`
  +.foo.h
   ----
   #ifndef FOO_H
   #define FOO_H
  
positive.code: ----
  
  [source,c]
  .`foo.c`
  ----
  
  #include "foo.h"
  
negative.code: 	$(RM) *.o *.so*
  ----
  
  <1> the name and version of the library are just parameters
  <2> it creates a shared object with a proper soname
  <3> it compiles the library with debugging symbols, optimization and 
    strict error checking
  