gnu.cfg: Added support for canonicalize_file_name() function.

cfg/gnu.cfg

@@ -396,6 +396,16 @@
     </arg>
     <leak-ignore/>
   </function>
+  <!-- char *canonicalize_file_name(const char *path); -->
+  <function name="canonicalize_file_name">
+    <use-retval/>
+    <noreturn>false</noreturn>
+    <leak-ignore/>
+    <arg nr="1">
+      <not-null/>
+    </arg>
+    <arg nr="2"/>
+  </function>  
   <!-- see https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html -->
   <define name="__builtin_expect(X,Y)" value="(X)"/>
   <!-- see http://kernelnewbies.org/FAQ/LikelyUnlikely -->