posix.cfg: Fixed FP for getcwd().First and second parameter is allowed to be zero.

cfg/posix.cfg

@@ -9,8 +9,7 @@
   <function name="mktemp"> <noreturn>false</noreturn> <arg nr="1"><not-uninit/><not-null/></arg> <leak-ignore/> </function>
   <function name="getcwd">
     <noreturn>false</noreturn>
-    <arg nr="1"><not-null/></arg>
-    <arg nr="2"><not-uninit/><not-null/></arg>
+    <arg nr="2"><not-uninit/></arg>
     <leak-ignore/>
   </function>
   <function name="mkdir">

test/testnullpointer.cpp

@@ -2615,6 +2615,9 @@ private:
         check("void f(char *p){ int i = 0; mkdir (p, i);}");
         ASSERT_EQUALS("",errout.str());
 
+        check("void f(){ getcwd (0, 0);}");
+        ASSERT_EQUALS("",errout.str());
+
         check("void f(char *p){ mkdir (p, *0);}");
         ASSERT_EQUALS("[test.cpp:1]: (error) Null pointer dereference\n",errout.str());
     }